Mechanical, structural, and morphological differences in the iliac arteries.

Iliac arteries play a crucial role in peripheral blood circulation. They are susceptible to various diseases, including aneurysms and atherosclerosis. Structure, material properties, and biomechanical forces acting on different regions of the iliac vasculature may contribute to the localization and progression of these pathologies. We examined 33 arterial specimens from common iliac (CI), external iliac (EI), and internal iliac (II) arteries obtained from 11 human donors (62 ± 12 years). We conducted morphometric, mechanical, and structural analyses using planar biaxial tests, constitutive modeling, and bi-directional histology on transverse and axial sections. The iliac arteries exhibited increased tortuosity and varying disease distribution with age. CI and II arteries displayed non-uniform age-related disease progression around their circumference, while EI remained healthy even in older individuals. Trends in load-free and stress-free thickness varied along the iliac vasculature. Longitudinally, EI exhibited the highest compliance compared to other iliac vessels. In contrast, CI was stiffest longitudinally, and EI was the stiffest circumferentially. Material parameters for all iliac vessels are reported for four common constitutive relations. Elastin near the internal elastic lamina displayed greater waviness in EI and II compared to CI. Also, EI had the least glycosaminoglycans (GAGs) and the highest elastin content. Our findings highlight variations in the morphological, mechanical, and structural properties of iliac arteries along their length. This data can inform vascular disease development and computational studies, and guide the development of biomimetic repair materials and devices tailored to specific iliac locations, improving vascular repair strategies.

Structural and Mechanical Properties of Human Superficial Femoral and Popliteal Arteries.

The femoropopliteal artery (FPA) is the main artery in the lower limb. It supplies blood to the leg muscles and undergoes complex deformations during limb flexion. Atherosclerotic disease of the FPA (peripheral arterial disease, PAD) is a major public health burden, and despite advances in surgical and interventional therapies, the clinical outcomes of PAD repairs continue to be suboptimal, particularly in challenging calcified lesions and biomechanically active locations. A better understanding of human FPA mechanical and structural characteristics in relation to age, risk factors, and the severity of vascular disease can help develop more effective and longer-lasting treatments through computational modeling and device optimization. This review aims to summarize recent research on the main biomechanical and structural properties of human superficial femoral and popliteal arteries that comprise the FPA and describe their anatomy, composition, and mechanical behavior under different conditions.

Mechanical, structural, and physiologic differences between above and below-knee human arteries.

Peripheral Artery Disease (PAD) affects the lower extremities and frequently results in poor clinical outcomes, especially in the vessels below the knee. Understanding the biomechanical and structural characteristics of these arteries is important for improving treatment efficacy, but mechanical and structural data on tibial vessels remain limited. We compared the superficial femoral (SFA) and popliteal (PA) arteries that comprise the above-knee femoropopliteal (FPA) segment to the infrapopliteal (IPA) anterior tibial (AT), posterior tibial (PT), and fibular (FA) arteries from the same 15 human subjects (average age 52, range 42-67 years, 87 % male). Vessels were imaged using µCT, evaluated with biaxial mechanical testing and constitutive modeling, and assessed for elastin, collagen, smooth muscle cells (SMCs), and glycosaminoglycans (GAGs). IPAs were more often diseased or calcified compared to the FPAs. They were also twice smaller, 53 % thinner, and significantly stiffer than the FPA longitudinally, but not circumferentially. IPAs experienced 48 % higher physiologic longitudinal stresses (62 kPa) but 27 % lower circumferential stresses (24 kPa) and similar cardiac cycle stretch of <1.02 compared to the FPA. IPAs had lower longitudinal pre-stretch (1.12) than the FPAs (1.29), but there were no differences in the stored elastic energy during pulsation. The physiologic circumferential stiffness was similar in the above and below-knee arteries (718 kPa vs 754 kPa). Structurally, IPAs had less elastin, collagen, and GAGs than the FPA, but maintained similar SMC content. Our findings contribute to a better understanding of segment-specific human lower extremity artery biomechanics and may inform the development of better medical devices for PAD treatment. STATEMENT OF SIGNIFICANCE: Peripheral Artery Disease (PAD) in the lower extremity arteries exhibits distinct characteristics and results in different clinical outcomes when treating arteries above and below the knee. However, their mechanical, structural, and physiologic differences are poorly understood. Our study compared above- and below-knee arteries from the same middle-aged human subjects and demonstrated distinct differences in size, structure, and mechanical properties, leading to variations in their physiological behavior. These insights could pave the way for creating location-specific medical devices and treatments for PAD, offering a more effective approach to its management. Our findings provide new, important perspectives for clinicians, researchers, and medical device developers interested in treating PAD in both above- and below-knee locations.

Variability in structure, morphology, and mechanical properties of the descending thoracic and infrarenal aorta around their circumference.

Aortic diseases, such as aneurysms, atherosclerosis, and dissections, demonstrate a preferential development and progression around the aortic circumference, resulting in a highly heterogeneous disease state around the circumference. Differences in the aorta's structural composition and mechanical properties may be partly responsible for this phenomenon. Our goal in this study was to analyze the mechanical and structural properties of the human aorta at its lateral, anterior, posterior, and medial quadrants in two regions prone to circumferentially inhomogeneous diseases, descending Thoracic Aorta (TA) and Infrarenal Aorta (IFR). Human aortas were obtained from 10 donors (64 ± 11 years) and dissected from their loose surrounding tissue. Mechanical properties were determined in all four quadrants of TA and IFR using planar biaxial testing and fitted to three common constitutive models. The structure of tissues was assessed using Movat Pentachrome stained histology slides. We observed that the anterior quadrant exhibited the greatest thickness, followed by the lateral region, in both the TA and IFR. In TA, the posterior wall appeared as the stiffest location in most samples, while in IFR, the anterior wall was the stiffest. We observed a higher glycosaminoglycans content in the lateral and posterior regions of the IFR. We found elastin density to be similar in TA lateral, anterior, and posterior quadrants, while in IFR, the anterior region demonstrated the highest elastin density. Despite significant variations between subjects, this study highlights the distinct morphometrical, mechanical, and structural properties between the quadrants of both TA and IFR.

Histology Image Viewer and Converter (HIVC): A High-Speed Freeware Software to View and Convert Whole Slide Histology Images.

Histology images are widely used to assess the microstructure of biological tissues, but scanners often save images in bulky SVS and multi-layered TIFF formats. These formats were designed to archive image blocks and high-resolution textual information and are not compatible with conventional image analysis software. Our goal was to create a freeware Histology Image Viewer and Converter (HIVC) with a graphical user interface that allows viewing and converting whole-slide images in batch. HIVC was developed using C# Language for Windows x64 operating system. HIVC's performance was assessed by converting 20 whole-slide images to a JPG format at 20x and 40x resolution and comparing the results to ImageJ, Cell Profiler, QuPath, Nanoborb, and Aperio ImageScope. HIVC was more than 8-times faster in converting images than other software packages. This software allows high-speed batch conversion of histology images to traditional formats, permitting platform-independent secondary analyses.

Human osteosarcoma cells in response to ELF-MF: Morphological remodeling compared to cell proliferation.

Purpose: The present study aimed to assess the effects of extremely low-frequency electromagnetic fields (ELF-MF) on structural changes of human osteosarcoma cells by analyzing the stained cytoskeleton for assessing the relationship between the fractal dimension parameter and proliferation rate of radiation-induced cells. Materials and Methods: In this study, 2-mT magnetic fields with various waveforms, including sinusoidal, triangular, and pulsed shapes, were employed to determine the biological effects of ELF-EMF on the human osteosarcoma MG-63 cell line. All experiments were performed in two modes: continuous exposure at 3 h and fractionated irradiations at 3 consecutive days. Afterward, the proliferation assay was implemented for assessing the cell proliferation in each group. Moreover, immunofluorescence staining and confocal imaging were performed to determine the cell shape index. Furthermore, fractal dimension analysis was carried out by processing morphological images. Results: The proliferation and shape index parameters of radiation-induced osteosarcomas significantly decreased compared with non-irradiated cells. In addition, fractal dimensions significantly increased following fractionated exposure at 3 consecutive days. Conclusions: Assessing the fractal dimensions can be considered as a new morphological index for the prognosis of the structural remodeling of human osteosarcoma cells in response to fractionated irradiation of ELF-MF. In addition, various waveforms induce a similar effect on morphological remodeling and cell proliferation.

A viscoelastic constitutive model for human femoropopliteal arteries.

High failure rates present challenges for surgical and interventional therapies for peripheral artery disease of the femoropopliteal artery (FPA). The FPA's demanding biomechanical environment necessitates complex interactions with repair devices and materials. While a comprehensive understanding of the FPA's mechanical characteristics could improve medical treatments, the viscoelastic properties of these muscular arteries remain poorly understood, and the constitutive model describing their time-dependent behavior is absent. We introduce a new viscoelastic constitutive model for the human FPA grounded in its microstructural composition. The model is capable of detailing the contributions of each intramural component to the overall viscoelastic response. Our model was developed utilizing fractional viscoelasticity and tested using biaxial experimental data with hysteresis and relaxation collected from 10 healthy human subjects aged 57 to 65 and further optimized for high throughput and automation. The model accurately described the experimental data, capturing significant nonlinearity and hysteresis that were particularly pronounced circumferentially, and tracked the contribution of passive smooth muscle cells to viscoelasticity that was twice that of the collagen fibers. The high-throughput parameter estimation procedure we developed included a specialized objective function and modifications to enhance convergence for the common exponential-type fiber laws, facilitating computational implementation. Our new model delineates the time-dependent behavior of human FPAs, which will improve the fidelity of computational simulations investigating device-artery interactions and contribute to their greater physical accuracy. Moreover, it serves as a useful tool to investigate the contribution of arterial constituents to overall tissue viscoelasticity, thereby expanding our knowledge of arterial mechanophysiology. STATEMENT OF SIGNIFICANCE: The demanding biomechanical environment of the femoropopliteal artery (FPA) necessitates complex interactions with repair devices and materials, but the viscoelastic properties of these muscular arteries remain poorly understood with the constitutive model describing their time-dependent behavior being absent. We hereby introduce the first viscoelastic constitutive model for the human FPA grounded in its microstructures. This model was tested using biaxial mechanical data collected from 10 healthy human subjects between the ages of 57 to 65. It can detail the contributions of each intramural component to the overall viscoelastic response, showing that the contribution of passive smooth muscle cells to viscoelasticity is twice that of collagen fibers. The usefulness of this model as tool to better understand arterial mechanophysiology was demonstrated.

High-resolution micro-cavity filling sensing by fiber optic interferometry.

In the last decade, new potential applications of micro- and nano-products in telecommunication, medical diagnostics, photovoltaic, and optoelectronic systems have increased the interest to develop micro-engineering technologies. Injection molding of polymeric materials is a recent method being adapted for serial manufacturing of optic components and packaging at the micro- and nano-scale. Quality assurance of replication into small cavities is an important but underdeveloped factor that is needed to ensure high production efficiency in any micro-fabrication industry. In this work, we introduce a fiber-based interferometric measurement sensor to monitor the cavity filling of optical microstructures fabricated into a macroscopic molding die. The interferometer was capable of resolving melt front motion into the microcavity to the point of complete filling as verified by atomic force microscopy. Despite the low reflectivity of the transparent polymer and unoptimized reflected light collection optics, this system is capable of monitoring polymer movement during the course of filling and detecting the completion of the process. The simplicity and flexibility of the technology could allow eventual instrumentation of injection molds, embossing, and nanoimprint tooling suitably modified with a small optical window to accommodate light from an optical fiber. This would provide a solution to the challenging problem of monitoring local, nanometer scale filling processes.

Breathing-induced Errors in Quantification and Description of Dominant Intra-Prostatic Lesions (Dils) in PET Images: A Simulation Study by Means of The 4D NCAT Phantom.

Background: Respiratory movement and the motion range of the diaphragm can affect the quality and quantity of prostate images. Objective: This study aimed to investigate the magnitude of respiratory-induced errors to determine Dominant Intra- prostatic Lesions (DILs) in positron emission tomography (PET) images. Material and Methods: In this simulation study, we employed the 4D NURBS-based cardiac-torso (4D-NCAT) phantom with a realistic breathing model to simulate the respiratory cycles of a patient to assess the displacement, volume, maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), signal to noise ratio (SNR), and the contrast of DILs in frames within the respiratory cycle. Results: Respiration in a diaphragm motion resulted in the maximum superior-inferior displacement of 3.9 and 6.1 mm, and the diaphragm motion amplitudes of 20 and 35 mm. In a no-motion image, the volume measurement of DILs had the smallest percentage of errors. Compared with the no-motion method, the percentages of errors in the average method in 20 and 35 mm- diaphragm motion were 25% and 105%, respectively. The motion effect was significantly reduced in terms of the values of SUVmax and SUVmean in comparison with the values of SUVmax and SUVmean in no- motion images. The contrast values in respiratory cycle frames were at a range of 3.3-19.2 mm and 6.5-46 for diaphragm movements' amplitudes of 20 and 35 mm. Conclusion: The respiratory movement errors in quantification and delineation of DILs were highly dependent on the range of motion, while the average method was not suitable to precisely delineate DILs in PET/CT in the dose-painting technique.

A method of assessing peripheral stent abrasiveness under cyclic deformations experienced during limb movement.

Poor outcomes of peripheral arterial disease stenting are often attributed to the inability of stents to accommodate the complex biomechanics of the flexed lower limb. Abrasion damage caused by rubbing of the stent against the artery wall during limb movement plays a significant role in reconstruction failure but has not been characterized. Our goals were to develop a method of assessing the abrasiveness of peripheral nitinol stents and apply it to several commercial devices. Misago, AbsolutePro, Innova, Zilver, SmartControl, SmartFlex, and Supera stents were deployed inside electrospun nanofibrillar tubes with femoropopliteal artery-mimicking mechanical properties and subjected to cyclic axial compression (25%), bending (90°), and torsion (26°/cm) equivalent to five life-years of severe limb flexions. Abrasion was assessed using an abrasion damage score (ADS, range 1-7) for each deformation mode. Misago produced the least abrasion and no stent fractures (ADS 3). Innova caused small abrasion under compression and torsion but large damage under bending (ADS 7). Supera performed well under bending and compression but caused damage under torsion (ADS 8). AbsolutePro produced significant abrasion under bending and compression but less damage under torsion (ADS 12). Zilver fractured under all three deformations and severely abraded the tube under bending and compression (ADS 15). SmartControl and SmartFlex fractured under all three deformations and produced significant abrasion due to strut penetration (ADS 20 and 21). ADS strongly correlated with clinical 12-month primary patency and target lesion revascularization rates, and the described method of assessing peripheral stent abrasiveness can guide device selection and development. STATEMENT OF SIGNIFICANCE: Poor outcomes of peripheral arterial disease stenting are related to the inability of stents to accommodate the complex biomechanics of the flexed lower limb. Abrasion damage caused by rubbing of the stent against the artery wall during limb movement plays a significant role in reconstruction failure but has not been characterized. Our study presents the first attempt at assessing peripheral stent abrasiveness, and the proposed method is applied to compare the abrasion damage caused by Misago, AbsolutePro, Innova, Zilver, SmartControl, SmartFlex, and Supera peripheral stents using artery-mimicking synthetic tubes and cyclic deformations equivalent to five life-years of severe limb flexions. The abrasion damage caused by stents strongly correlates with their clinical 12-month primary patency and target lesion revascularization rates, and the described methodology can be used as a cost-effective and controlled way of assessing stent performance, which can guide device selection and development.

Evaluation of Dose-Painting in the Dominant Intraprostatic Lesions by Radiobiological Parameters using 68Ga- PSMA PET/CT.

Background: Patients diagnosed with dominant intraprostatic lesions (DIL) may need radiation doses over than 80 Gy. Dose-painting by contours (DPC) is a useful technique which helps the patients. Dose-painting approach need to be evaluated. Objective: To evaluate the DCP technique in the case of boosting the DILs by radiobiological parameters, tumor control probability (TCP), and normal tissue complication probability (NTCP) via PET/CT images traced by 68Ga-PSMA. Material and Methods: In this analytical study, 68Ga-PSMA PET/CT images were obtained from patients with DILs that were delineated using the Fuzzy c-mean (FCM) algorithm and thresholding methods. The protocol of therapy included two phases; at the first phase (ph1), a total dose of 72 Gy in 36 fractions were delivered to the planning target volume (PTV1); the seconds phase consisted of the application of variable doses to the PTV2. Moreover, two concepts were also considered to calculate the TCP using the Zaider-Minerbo model. Results: The lowest volume in DILs belonged to the DIL1 extracted by the FCM method. According to dose-volume parameters of the rectum and bladder, by the increase in the PTV dose higher than 92 Gy, the amounts of rectum and bladder doses are increased. There was no difference between the TCPs of DILs at doses higher than 86 Gy and 100 Gy for ordinary and high clone density, respectively. Conclusion: Consequently, our dose-painting approach for DILs, extracted by the FCM method via PET/CT images, can reduce the total dose for prostate radiation with 100% tumor control and less normal tissue complications.

EMF promote BMSCs differentiation and functional recovery in hemiparkinsonian rats.

Bone marrow mesenchymal stem cells (BMSCs) have self-renewal ability while maintaining the proliferation facility. The BMSCs reproducing ability could affect by electromagnetic fields (EMFs) as a physical inducing factor. We focused on the EMF (400 µT, 75 Hz) exposed multi-potential BMSCs which differentiated and successfully implanted in the substantia nigra pars compacta (SNpc) of Parkinson's disease rat model. The purified BMSCs are exposed to sinusoidal and square waveform EMF (1 h/1 week or 7 h/1 day) then injected into the left SNpc of Parkinson's rats. To evaluate the morphology of EMF exposed BMSCs, the cresyl violet staining labeled the Nissl bodies. After evaluation of the rat's activity by behavioral tests (open-field and rotarod tests), the brains were obtained for the preparation of SNpc blocks and carry out the cresyl violet staining. Cell morphology proved most cell differentiation to neurons in the sinusoidal EMF groups. In the sinusoidal EMF exposure groups, large and small neurons were seen with apparent synapses. Although in the square EMF exposed groups some neurons were seen, most of the differentiated cells were astrocytes, microglia, and oligodendrocyte. The results confirmed an improvement in locomotors' activity of BMSC alone and sinusoidal EMF exposed groups. We presented a low-frequency EMF (75 Hz) to promote the capability of BMSC proliferation, differentiation to neurons and glial cells, and motor coordination activity in the treatment of hemiparkinsonian rats.

Photobiomodulation Therapy Affects the Elastic Modulus, Cytoskeletal Rearrangement and Migration Capability of Human Osteosarcoma Cells.

Photobiomodulation (PBM) therapy utilizes low-power lasers to modulate the viability of living human cells and leads to changes in proliferation, differentiation, adhesion and gene expression, even though the rearrangement of cytoskeleton was not previously studied. The present study aims to evaluate the photobiological effects on the elastic behavior of human osteosarcoma cells (MG-63) and their morphological changes. Fluorescence staining, confocal imaging and atomic force microscopy (AFM) topography were performed to study the effects of PBM therapy with the exposure of 532 nm-25mW, 650 nm-3mW, 650 nm-150mW and 780 nm-70mW beams following the 5-min continuous irradiation. The area of each beam was 3.14cm2 with a source-surface distance of 20 cm. Besides the cell proliferation assessment, the migratory potential of MG-63 was determined with the wound healing technique. The results indicated an increase in stiffness and shape index of radiation-induced cells 24 h after exposure along with the obvious F-actins changes. But, cell stiffening was not observed 72 h after 532 nm laser irradiation. Also, a decrease in the migration rate was seen in all of the groups after 72 h of irradiation except cells treated with 532 nm wavelength. However, 532 nm laser beams increase the migratory potential 24 h after exposure. Within 72 h after irradiation, the cell proliferation was only affected by applying 532 nm and 650 nm-150mW laser beams. It was concluded that applying photobiomodulation with wavelengths of 650 nm (at both utilized powers) and 780 nm alters the migration capability and provides a quantitative description of cytoskeletal changes. Moreover, membrane stiffening can be considered as the biological marker of PBM treatments.

Assessment Relation of Myocardial Detector Counts and Administered Activity of 99mTc-SestaMIBI in MPI: The Effects of Body Weight, BMI, and Gender.

INTRODUCTION: In myocardial perfusion imaging, reducing the number of photons in images of obese patients causes poor image quality. To solve this problem, we need to inject the tracer according to the patients' weight. Therefore, this study aimed to investigate the relationship between myocardial photon counts with patients' weight, BMI, and gender. MATERIALS AND METHODS: A total of 129 patients underwent myocardial perfusion imaging in a twoday stress-first protocol, but only rest images were included in this study. Multiplication factor was used to determine the amount of radiopharmaceutical activity injected into the patients. For evaluating the effect of gender, the photon counts of 22 female patients were also assessed when the breast tissue was pulled upward (Breast Up). The total myocardial detector counts in the raw images were calculated from the summation of 32 projections. A multiple linear regression test was used to simultaneously examine the effects of weight, BMI, and gender on photon counts. RESULTS: There was no significant relationship between photon counts and patients' weight (p=0.129) and BMI (0.406), but gender had significant effects on photon counts, and myocardial detector counts were found to be higher in males (p=0.00). There was a statistically significant difference between the images of Breast Up and Non-Breast Up, and myocardial detector counts were higher in the Breast Up imaging method (p=0.00). CONCLUSION: Using the bodyweight formula, the image quality was comparable in obese and lean patients, but myocardial detector counts were lower in females, and this formula needs to be adjusted according to the patient's gender.

Safe balloon inflation parameters for resuscitative endovascular balloon occlusion of the aorta.

BACKGROUND: Noncompressible hemorrhage is a leading cause of preventable death in civilian and military trauma populations. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a promising method for controlling noncompressible hemorrhage, but safe balloon inflation parameters are not well defined. Our goal was to determine the balloon inflation parameters associated with benchtop flow occlusion and aortic/balloon rupture in ex vivo human aortas and test the hypothesis that optimal balloon inflation characteristics depend on systolic pressure and subject demographics. METHODS: Aortic occlusion parameters in human thoracic aortas (TAs) and abdominal aortas (AAs) from 79 tissue donors (median ± SD age, 52 ± 18 years [range, 13-75 years]; male, 52; female, 27) were recorded under 100/40, 150/40, and 200/40 mm Hg flow pressures for ER-REBOA and Coda balloons. Rupture tests were done with Coda balloons only without flow. RESULTS: In the TA, the average balloon inflation volumes and pressures resulting in 100/40 mm Hg flow occlusion were 11.7 ± 3.8 mL and 174 ± 65 mm Hg for the ER-REBOA, and 10.6 ± 4.3 mL and 94 ± 57 mm Hg for the Coda balloons. In the AA, these values were 6.2 ± 2.6 mL and 110 ± 47 mm Hg for the ER-REBOA, and 5.9 ± 2.2 mL and 71 ± 30 mm Hg for the Coda. The average balloon inflation parameters associated with aortic/Coda balloon rupture were 39.1 ± 6.5 mL and 1,284 ± 385 mm Hg in the TA, and 27.7 ± 7.7 mL and 1,410 ± 483 mm Hg in the AA. Age, sex, and systolic pressure all had significant effects on balloon occlusion and rupture parameters. CONCLUSION: Optimal balloon inflation parameters depend on anatomical, physiological, and demographic characteristics. Pressure-guided rather than volume-guided balloon inflation may reduce the risk of aortic rupture. These results can be used to help improve the safety of REBOA procedures and devices.

Calcification prevalence in different vascular zones and its association with demographics, risk factors, and morphometry.

Vascular calcification is associated with a higher incidence of cardiovascular events, but its prevalence in different vascular zones and the influence of demographics, risk factors, and morphometry remain insufficiently understood. Computerized tomography angiography scans from 211 subjects 5-93 yr old (mean age 47 ± 24 yr, 127 M/84 F) were used to build 3D vascular reconstructions and measure arterial diameters, tortuosity, and calcification volumes in six vascular zones spanning from the ascending thoracic aorta to the pelvic arteries. A machine learning random forest algorithm was used to determine the associations between calcification in each zone with demographics, risk factors, and vascular morphometry. Calcification appeared during the fourth decade of life and was present in all subjects after 65 yr. The abdominal aorta and the iliofemoral segment were the first to develop calcification, whereas the ascending thoracic aorta was the last. Demographics and risk factors explained 33-59% of the variation in calcification. Age, creatinine level, body mass index, coronary artery disease, and hypertension were the strongest contributors, whereas the effects of sex, race, tobacco use, diabetes, dyslipidemia, and alcohol and substance use disorders on calcification were small. Vascular morphometry did not directly and independently affect calcium burden. Vascular zones develop calcification asynchronously, with distal segments calcifying first. Understanding the influence of demographics and risk factors on calcium prevalence can help better understand the disease pathophysiology and may help with the early identification of patients that are at higher risk of cardiovascular events.NEW & NOTEWORTHY We investigated the prevalence of vascular calcification in different zones of the aorta and pelvic arteries using computerized tomography angiography reconstructions and have applied machine learning to determine how calcification is affected by demographics, risk factors, and morphometry. The presented data can help identify patients at higher risk of developing vascular calcification that may lead to cardiovascular events.

A comparison of 8 and 16 frames gated SPECT imaging for determination of left ventricular volumes and ejection fraction: effects of gender and myocardial counts.

In myocardial gated SPECT imaging each cardiac cycle is divided into 8 or 16 temporal frames and the cause of the difference between 8 and 16 frames is not specified exactly. The aim of this study was to investigate the effect of myocardial detector counts and gender on the difference between 8 and 16 frames and also to compare the LVEF obtained by 8 and 16 frames with echocardiography. The study population included 84 patients who underwent gated SPECT imaging. Left ventricular parameters were assessed on 8 and 16 frames gated SPECT. LVEF was also measured with two-dimensional echocardiography within 5-10 days after gated SPECT imaging. There was a good correlation between 8 and 16 frames for calculation of LVEF (p = 0.00, r = 0.860), EDV (p = 0.00, r = 0.965) and ESV (p = 0.00, r = 0.956) in all patients. But the difference between 8 and 16 frames for calculation of LVEF (p = 0.00), EDV (p = 0.014) and ESV (p = 0.00) was statistically significant. This difference was assessed separately in females, males, patients with high photon counts and patients with low photon counts and in all subgroups was statistically significant difference in the estimation of LVEF and ESV (p < 0.05) but no significant difference in the estimation of EDV (p > 0.05). Echocardiography resulted in smaller LVEF as compared to 8 and 16 frames gated SPECT studies and there was a significant difference between the two methods (p = 0.00). The myocardial detector counts and gender have no effect on the difference between 8 and 16 frames methods and the LVEF on echocardiography is smaller than the gated SPECT, but the 8-frame is closer to echocardiography.

EMF frequency dependent differentiation of rat bone marrow mesenchymal stem cells to astrocyte cells.

The numerous factors regulate the bone marrow mesenchymal stem cell (BMMSC) self-renewal and differentiation response. We aimed to analyze the influence of electromagnetic field (EMF) as an external inducing factor on rat BMMSC differentiation and proliferation to neuron and astrocyte cells. BMMSCs extracted from the rats femurs and tibias and incubated in a cell-cultured CO2 incubator. After the third passages, the plates selected randomly and then divided into seven groups (Sham exposed, three groups of square, and three groups of sinusoidal waveform EMF (25, 50, and 75 Hz, 400 µT, 1 h/day). The BMMSCs exposed to EMF at the middle of a Helmholtz coil for 7 days. The viable cell counting and proliferation performed by the MTT test and BMMSC differentiation into the neuron and the astrocyte cell was studied by immunocytochemistry staining. The results confirmed BMMSC viability and proliferation rate reduction in sinusoidal 25 Hz, square 50 Hz and sinusoidal 75 Hz EMF groups compare to sham. The maximum BMMSC differentiation to neuron was considered in sinusoidal 50 Hz and 75 Hz EMF groups. The increase of BMMSC differentiation to astrocyte cell was frequency dependent and the most differentiation was shown in square 75 Hz, and sinusoidal 75 Hz EMF groups. In conclusion, the results suggest that both square and sinusoidal EMF could affect BMMSC development and differentiation to neuron and astrocyte cells. Further studies for the consequence of EMF with wider flux density and frequency on BMMSC are recommended.

Mechanical, structural, and physiologic differences in human elastic and muscular arteries of different ages: Comparison of the descending thoracic aorta to the superficial femoral artery.

Elastic and muscular arteries differ in structure, function, and mechanical properties, and may adapt differently to aging. We compared the descending thoracic aortas (TA) and the superficial femoral arteries (SFA) of 27 tissue donors (average 41±18 years, range 13-73 years) using planar biaxial testing, constitutive modeling, and bidirectional histology. Both TAs and SFAs increased in size with age, with the outer radius increasing more than the inner radius, but the TAs thickened 6-fold and widened 3-fold faster than the SFAs. The circumferential opening angle did not change in the TA, but increased 2.4-fold in the SFA. Young TAs were relatively isotropic, but the anisotropy increased with age due to longitudinal stiffening. SFAs were 51% more compliant longitudinally irrespective of age. Older TAs and SFAs were stiffer, but the SFA stiffened 5.6-fold faster circumferentially than the TA. Physiologic stresses decreased with age in both arteries, with greater changes occurring longitudinally. TAs had larger circumferential, but smaller longitudinal stresses than the SFAs, larger cardiac cycle stretch, 36% lower circumferential stiffness, and 8-fold more elastic energy available for pulsation. TAs contained elastin sheets separated by smooth muscle cells (SMCs), collagen, and glycosaminoglycans, while the SFAs had SMCs, collagen, and longitudinal elastic fibers. With age, densities of elastin and SMCs decreased, collagen remained constant due to medial thickening, and the glycosaminoglycans increased. Elastic and muscular arteries demonstrate different morphological, mechanical, physiologic, and structural characteristics and adapt differently to aging. While the aortas remodel to preserve the Windkessel function, the SFAs maintain higher longitudinal compliance.