Calcium Distribution Research Articles

Tooth acellular extrinsic fibre cementum incremental lines in humans are formed by parallel branched Sharpey’s fibres and not by its mineral phase

In humans, the growth pattern of the acellular extrinsic fibre cementum (AEFC) has been useful to estimate the age-at-death. However, the structural organization behind such a pattern remains poorly understood. In this study tooth cementum from seven individuals from a Mexican modern skeletal series were analyzed with the aim of unveiling the AEFC collagenous and mineral structure using multimodal imaging approaches. The organization of collagen fibres was first determined using: light microscopy, transmission electron microscopy (TEM), electron tomography, and plasma FIB scanning electron microscopy (PFIB-SEM) tomography. The mineral properties were then investigated using: synchrotron small-angle X-ray scattering (SAXS) for T-parameter (correlation length between mineral particles); synchrotron X-ray diffraction (XRD) for L-parameter (mineral crystalline domain size estimation), alignment parameter (crystals preferred orientation) and lattice parameters a and c; as well as synchrotron X-ray fluorescence for spatial distribution of calcium, phosphorus and zinc. Results show that Sharpey’s fibres branched out fibres that cover and uncover other collagen bundles forming aligned arched structures that are joined by these same fibres but in a parallel fashion. The parallel fibres are not set as a continuum on the same plane and when they are superimposed project the AEFC incremental lines due to the collagen birefringence. The orientation of the apatite crystallites is subject to the arrangement of the collagen fibres, and the obtained parameter values along with the elemental distribution maps, revealed this mineral tissue as relatively homogeneous. Therefore, no intrinsic characteristics of the mineral phase could be associated with the alternating AEFC incremental pattern.

Automated multiclass segmentation, quantification, and visualization of the diseased aorta on hybrid PET/CT-SEQUOIA.

Cardiovascular disease is the most common cause of death worldwide, including infection and inflammation related conditions. Multiple studies have demonstrated potential advantages of hybrid positron emission tomography combined with computed tomography (PET/CT) as an adjunct to current clinical inflammatory and infectious biochemical markers. To quantitatively analyze vascular diseases at PET/CT, robust segmentation of the aorta is necessary. However, manual segmentation is extremely time-consuming and labor-intensive. To investigate the feasibility and accuracy of an automated tool to segment and quantify multiple parts of the diseased aorta on unenhanced low-dose computed tomography (LDCT) as an anatomical reference for PET-assessed vascular disease. A software pipeline was developed including automated segmentation using a 3D U-Net, calcium scoring, PET uptake quantification, background measurement, radiomics feature extraction, and 2D surface visualization of vessel wall calcium and tracer uptake distribution. To train the 3D U-Net, 352 non-contrast LDCTs from (2-[18F]FDG and Na[18F]F) PET/CTs performed in patients with various vascular pathologies with manual segmentation of the ascending aorta, aortic arch, descending aorta, and abdominal aorta were used. The last 22 consecutive scans were used as a hold-out internal test set. The remaining dataset was randomly split into training (n=264; 80%) and validation (n=66; 20%) sets. Further evaluation was performed on an external test set of 49 PET/CTs. The dice similarity coefficient (DSC) and Hausdorff distance (HD) were used to assess segmentation performance. Automatically obtained calcium scores and uptake values were compared with manual scoring obtained using clinical softwares (syngo.via and Affinity Viewer) in six patient images. intraclass correlation coefficients (ICC) were calculated to validate calcium and uptake values. Fully automated segmentation of the aorta using a 3D U-Net was feasible in LDCT obtained from PET/CT scans. The external test set yielded a DSC of 0.867±0.030 and HD of 1.0 [0.6-1.4] mm, similar to an open-source model with a DSC of 0.864±0.023 and HD of 1.4 [1.0-1.8] mm. Quantification of calcium and uptake values were in excellent agreement with clinical software (ICC: 1.00 [1.00-1.00] and 0.99 [0.93-1.00] for calcium and uptake values, respectively). We present an automated pipeline to segment the ascending aorta, aortic arch, descending aorta, and abdominal aorta on LDCT from PET/CT and to accurately provide uptake values, calcium scores, background measurement, radiomics features, and a 2D visualization. We call this algorithm SEQUOIA (SEgmentation, QUantification, and visualizatiOn of the dIseased Aorta) and is available at https://github.com/UMCG-CVI/SEQUOIA. This model could augment the utility of aortic evaluation at PET/CT studies tremendously, irrespective of the tracer, and potentially provide fast and reliable quantification of cardiovascular diseases in clinical practice, both for primary diagnosis and disease monitoring.

The bioelectric mechanisms of local calcium dynamics in cancer cell proliferation: an extension of the A549 in silico cell model.

Advances in molecular targeting of ion channels may open up new avenues for therapeutic approaches in cancer based on the cells' bioelectric properties. In addition to in-vitro or in-vivo models, in silico models can provide deeper insight into the complex role of electrophysiology in cancer and reveal the impact of altered ion channel expression and the membrane potential on malignant processes. The A549 in silico model is the first computational cancer whole-cell ion current model that simulates the bioelectric mechanisms of the human non-small cell lung cancer cell line A549 during the different phases of the cell cycle. This work extends the existing model with a detailed mathematical description of the store-operated Ca2+ entry (SOCE) and the complex local intracellular calcium dynamics, which significantly affect the entire electrophysiological properties of the cell and regulate cell cycle progression. The initial model was extended by a multicompartmental approach, addressing the heterogenous calcium profile and dynamics in the ER-PM junction provoked by local calcium entry of store-operated calcium channels (SOCs) and uptake by SERCA pumps. Changes of cytosolic calcium levels due to diffusion from the ER-PM junction, release from the ER by RyR channels and IP3 receptors, as well as corresponding PM channels were simulated and the dynamics evaluated based on calcium imaging data. The model parameters were fitted to available data from two published experimental studies, showing the function of CRAC channels and indirectly of IP3R, RyR and PMCA via changes of the cytosolic calcium levels. The proposed calcium description accurately reproduces the dynamics of calcium imaging data and simulates the SOCE mechanisms. In addition, simulations of the combined A549-SOCE model in distinct phases of the cell cycle demonstrate how Ca2+ - dynamics influence responding channels such as KCa, and consequently modulate the membrane potential accordingly. Local calcium distribution and time evolution in microdomains of the cell significantly impact the overall electrophysiological properties and exert control over cell cycle progression. By providing a more profound description, the extended A549-SOCE model represents an important step on the route towards a valid model for oncological research and in silico supported development of novel therapeutic strategies.

Nutritional Assessment and Comparison between Brown and Milled Rice Landraces (Anadi, Bhotange, and Kalo Nuniya) of Nepal

The main objective of this study was to assess and compare the nutritional quality of brown- and milled rice landraces (Kalo Nuniya, Anadi, and Bhotange) of Koshi Province. Paddy samples were cleaned to remove dockage and sun-dried until about 13-14% moisture to ensure maximum hulling- and milling recovery. Paddy samples were shelled and milled to obtain brown (unpolished) rice and milled (white or polished) rice, respectively and were stored in double-sealed re-closable low-density polyethylene (LDPE) zipper bags (62.5 µm) at ambient temperature (23-27°C) until analysis. As expected, brown rices had better nutritional profiles than their milled counterparts with significantly higher (p<0.05) crude fat (2.99± 0.10 − 3.99 ± 0.09%), crude fiber (0.12 ± 0.00 − 0.70 ± 0.02%), and total ash (1.53 ± 0.2 − 3.71 ± 0.30%) content. Among the brown rices, Anadi brown had better nutritional profile with the highest iron (1.56 ± 0.14 mg/ 100 g), calcium (86.4 ± 3.30 mg/100 g), total ash (3.71 ± 0.30%), crude fiber (0.70 ± 0.02%), and crude fat content (3.99 ± 0.09%). Bhotange and Kalo Nuniya had uniform distribution of iron and calcium, respectively, throughout the entire rice kernel.

EDXRF and the relative presence of K, Ca, Fe and as in amyloidogenic tissues

Trace and minor elements play crucial roles in a variety of biological processes, including amyloid fibrils formation. Mechanisms include activation or inhibition of enzymatic reactions, competition between elements and metal proteins for binding positions, also changes to the permeability of cellular membranes. These may influence carcinogenic processes, with trace and minor element concentrations in normal and amyloid tissues potentially aiding in cancer diagnosis and etiology. With the analytical capability of the spectroscopic technique X-ray fluorescence (XRF), this can be used to detect and quantify the presence of elements in amyloid characterization, two of the trace elements known to be associated with amyloid fibrils. In present work, involving samples from a total of 22 subjects, samples of normal and amyloid-containing tissues of heart, kidney, thyroid, and other tissue organs were obtained, analyzed via energy-dispersive X-ray fluorescence (EDXRF). The elemental distribution of potassium (K), calcium (Ca), arsenic (As), and iron (Fe) was examined in both normal and amyloidogenic tissues using perpetual thin slices. In amyloidogenic tissues the levels of K, Ca, and Fe were found to be less than in corresponding normal tissues. Moreover, the presence of As was only observed in amyloidogenic samples; in a few cases in which there was an absence of As, amyloid samples were found to contain Fe. Analysis of arsenic in amyloid plaques has previously been difficult, often producing contradictory results. Using the present EDXRF facility we could distinguish between amyloidogenic and normal samples, with potential correlations in respect of the presence or concentration of specific elements.

Recurrent Valve Frame Infolding in the 34mm Self-Expanding Medtronic Evolut Pro+ Transcatheter Valve System: A Single Centre Experience

Valve frame infolding (VFI) is a rare complication (1-3%) of transcatheter aortic valve implantation (TAVI), which primarily occurs in large sized self-expanding valves. We report the incidence of VFI in a small group of patients with highly calcified and extra-large aortic annuli, who underwent implantation of the newer generation 34mm Medtronic Evolut Pro+ (EP+) valve system. A retrospective review was conducted on all patients presenting to a single centre experienced with TAVI in Sydney, NSW, Australia, between June and October 2022, for transfemoral TAVI using the Medtronic 34mm EP+ valve system. VFI was diagnosed using fluoroscopy, and pre-procedure computed tomography (CT) was analysed offline. VFI occurred in four of 10 patients who underwent TAVI using the 34mm EP+ system. Between VFI and non-VFI patients, the annular size, aortic angulation and total calcium volume was similar. Calcium distribution between the coronary cusps was symmetrical in non-VFI patients (37%, 33% and 30%), compared to 52% in the non-coronary cusp (NCC) in VFI patients. The mean ellipticity index was higher in VFI versus non-VFI patients (22% vs 14%). The 34mm Medtronic EP+ valve system is vital for safe and effective treatment of a niche subgroup of patients with extra-large annuli and extensive calcification, however operators should be aware of the increased incidence of VFI. Heavy eccentric calcification at the NCC, as well as using the cusp-overlap implant technique may exacerbate VFI, while multiplanar fluoroscopic screening may improve recognition.

Relation between coronary artery calcium score and cardiovascular events in Hodgkin lymphoma survivors: a cross-sectional matched cohort study

Abstract Introduction Long-term survival after Hodgkin lymphoma (HL) has improved significantly over the past years, due to enhanced treatment options. Thoracic radiotherapy is still one of the corner stones of HL treatment, but is associated with increased risk of cardiovascular events. As HL is often diagnosed at young age, long-term follow-up including screening for coronary artery disease (CAD) is recommended. Purpose This study aims to evaluate the presence and distribution of coronary artery calcium in relation to cardiovascular events in HL patients treated with thoracic radiotherapy compared to a non-cancer control group. Methods Consecutive HL patients treated with thoracic radiotherapy, who underwent evaluation for asymptomatic CAD with coronary computed tomography angiography (CCTA) > 10 years after irradiation between 2002 and 2022 were included. HL patients were matched 1:1 to non-cancer patients on gender, age, cardiovascular risk factors and statin use. Differences in coronary artery calcium score (CACS), stenosis severity and cardiovascular events between the two groups were compared. Results The total study population consisted of 194 patients of whom 97 patients had a prior HL diagnosis and 97 patients had no history of cancer. Elevated CACS was seen in 50.5% of the HL patients (N=49) and 30.9% of the control patients (N=30). HL survivors had an odds ratio of 2.28 [95% CI: 1.22 – 4.28] for having a CACS > 0 compared to the matched non-cancer population (p=0.006). Distribution pattern of coronary calcium differed significantly with the prevalence of a CACS above the 90th percentile (17.5% in HL survivors versus 4.7% in the matched population, p=0.005). Also coronary artery stenosis was more prevalent in the HL population than in the control population (39.2% versus 15.5% respectively, p=<0.001). Nine HL patients experienced an event during the follow-up period including two patients with a CACS of zero. No events were observed in the control population. Conclusion This study shows that in a matched study population, HL survivors have a higher prevalence of a CACS > 0 and an increased risk of cardiovascular events after thoracic irradiation compared to a matched non-cancer control group.Distribution of CACS percentiles

Abstract 14960: Coronary Artery Calcium Distribution Patterns Are Independently Predictive of Adverse Cardiovascular Events: Observations From the Dallas Heart Study

Introduction: The coronary artery calcium (CAC) diffusivity index (DI) may improve risk stratification for those with Agatston CAC > 0 in older individuals. We aimed to assess whether the distribution of CAC would improve risk prediction of cardiovascular (CV) events beyond the traditional Agatston CAC score in a younger population. Methods: Among Dallas Heart Study 2 (DHS2) participants with Agatston CAC > 0 and no history of CVD (35% of entire cohort), we studied 1013 participants with CAC DI at DHS2. The raw CAC DI was calculated as 1 - (CAC in most affected vessel/total CAC) and categorized into concentrated (<25th%), standard (25-75th%), and diffuse (>75th%) patterns. Multivariable Cox proportional hazards regression and C statistics were calculated for coronary events (CHD) and all CVD, and all-cause mortality. Models were adjusted for total Agatston score, race, gender, BSA, smoking history, diabetes, and statin use. Results: Mean age of the DHS2 study cohort was 55 ± 9.4 years (48% women, 45% Black). The median follow up was 9 ± 2.5 years (55 CHD, 97 CVD, and 120 all-cause mortality events) (Figure, A) . CAC DI was modestly correlated with Agatston CAC (Spearman rho = 0.60, p<0.01). In models adjusted for total Agatston score, risk factors, and demographics, compared with a concentrated pattern, a diffuse CAC pattern was associated with incident CHD (HR [95%CI]: 5.32 [1.68-16.86]); CVD (HR [95%CI]: 3.21 [1.66-6.21]), and all-cause mortality (HR [95%CI]: 2.02 [1.18-3.47] (Figure, B) . Findings were similar for continuous CAC DI. Addition of continuous CAC DI to adjusted models including Agatston CAC improved the C-statistic for CHD (0.79 to 0.81, p<0.01) and CVD (0.71 to 0.73, p<0.01). Conclusions: Beyond the validated Agatston score, higher CAC DI at baseline improves risk prediction of incident CHD and CVD events in a younger population-based cohort. Further studies are warranted to evaluate the clinical utility of assessing distribution patterns of CAC.

Effects of titanium fluoride on caries inhibition and elemental distribution in the tooth structure: Comparisons with sodium fluoride at the same fluoride concentration and pH values

Titanium fluoride (TiF4) reduces mineral loss and lesion depth more effectively than sodium fluoride (NaF). However, the pH values of TiF4 and NaF solutions are different. This study aimed to evaluate the effects of TiF4 solution on the inhibition of demineralization and elemental distribution in root dentin in comparison with NaF solution at the same pH and fluoride concentrations. This study was conducted using 0.5% TiF4 or 0.675% NaF solution adjusted to pH 5 or pH 7. Bovine dentin specimens of 200 [Formula: see text]m thickness were subjected to pH cycling (pH 4.5 and 7.0; 6 cycles/day; simulated oral conditions) for eight weeks to prepare artificial carious dentin. During this cycle, the specimens were soaked in each solution once a week for 5 min. The control group involved no fluoride application during the test period. After cycling, the demineralization depth was measured and the calcium, fluorine, and titanium distributions were analyzed and calculated using an in-air micro-proton-induced X-ray emission (PIXE)/proton-induced gamma emission (PIGE) system at TIARA. At pH 7, TiF4 solution yielded a lower lesion depth than the NaF solution. The NaF solution at pH 7 showed lower fluorine concentration than that with the other fluoride solutions. Thus, TiF4 is more effective in inhibiting demineralization than NaF in a solution adjusted to pH 7. Moreover, the presence of titanium may strengthen the tooth structure.

Photon-Counting CT Material Decomposition in Bone Imaging.

The accurate screening of osteoporosis is important for identifying persons at risk. The diagnosis of bone conditions using dual X-ray absorptiometry is limited to extracting areal bone mineral density (BMD) and fails to provide any structural information. Computed tomography (CT) is excellent for morphological imaging but not ideal for material quantification. Advanced photon-counting detector CT (PCD-CT) possesses high spectral sensitivity and material decomposition capabilities to simultaneously determine qualitative and quantitative information. In this study, we explored the diagnostic utility of PCD-CT to provide high-resolution 3-D imaging of bone microarchitecture and composition for the sensitive diagnosis of bone in untreated and ovariectomized rats. PCD-CT accurately decomposed the calcium content within hydroxyapatite phantoms (r = 0.99). MicroCT analysis of tibial bone revealed significant differences in the morphological parameters between the untreated and ovariectomized samples. However, differences in the structural parameters of the mandible between the treatment groups were not observed. BMD determined with microCT and calcium concentration decomposed using PCD-CT differed significantly between the treatment groups in both the tibia and mandible. Quantitative analysis with PCD-CT is sensitive in determining the distribution of calcium and water components in bone and may have utility in the screening and diagnosis of bone conditions such as osteoporosis.

Enrichment of calcium in sea spray aerosol: insights from bulk measurements and individual particle analysis during the R/V Xuelong cruise in the summertime in Ross Sea, Antarctica

Abstract. Although calcium is known to be enriched in sea spray aerosols (SSAs), the factors that affect its enrichment remain ambiguous. In this study, we examine how environmental factors affect the distribution of water-soluble calcium (Ca2+) distribution in SSAs. We obtained our dataset from observations taken during the R/V Xuelong research cruise in the Ross Sea, Antarctica, from December 2017 to February 2018. Our observations showed that the enrichment of Ca2+ in aerosol samples was enhanced under specific conditions, including lower temperatures (<-3.5 ∘C), lower wind speeds (<7 m s−1), and the presence of sea ice. Our analysis of individual particle mass spectra revealed that a significant portion of calcium in SSAs was likely bound with organic matter (in the form of a single-particle type, OC-Ca, internally mixed organics with calcium). Our findings suggest that current estimations of Ca2+ enrichment based solely on water-soluble Ca2+ may be inaccurate. Our study is the first to observe a single-particle type dominated by calcium in the Antarctic atmosphere. Our findings suggest that future Antarctic atmospheric modeling should take into account the environmental behavior of individual OC-Ca particles. With the ongoing global warming and retreat of sea ice, it is essential to understand the mechanisms of calcium enrichment and the mixing state of individual particles to better comprehend the interactions between aerosols, clouds, and climate during the Antarctic summer.

Increased content and uniformity of enzyme-induced calcite precipitation realized by prehydrolysis and an accelerated injection rate

The utilization of enzyme-induced calcium carbonate precipitation (EICP) to consolidate aeolian sand has received significant attention in recent years. When EICP was used and cementing solution was injected in stages, the calcium carbonate content and uniformity were not improved simultaneously. A method is proposed to alleviate this problem by pre-reacting urea and urease before injecting the cementing solution and speeding up the injection rate. Experiments were designed to compare staged injections of EICP-cemented aeolian sand with and without the use of prehydrolysis and with different injection rates. The results show that 1) at the same injection rate, the content of calcium carbonate in the prehydrolysis samples after 12 injections was 66.1% higher than that in the samples without prehydrolysis. 2) When using prehydrolysis, the calcium carbonate content as a function of the injection rate decreased in the following order: 10 mL/min >15 mL/min >7.5 mL/min. The highest amount of calcium carbonate was generated at an injection rate of 10 mL/min and was mainly distributed on the surface. The calcium carbonate generated with an injection rate of 15 mL/min was uniformly distributed in the sand. These results indicate that the method could improve the efficiency of calcium carbonate generation and distribution uniformity, and could also be applied to form a hard crust on the surface of sandy soil or for reinforcing sandy soil by multiple injections.

Use of Coronary Artery Calcium Quantification and Distribution for Coronary Vascular Disease Risk Reclassification in a Primary Prevention Setting

In a large screening program of asymptomatic middle-aged individuals, we sought to assess the degree of risk reclassification provided by comparing multiethnic study on subclinical atherosclerosis coronary artery calcium scoring (CACS) versus atherosclerotic cardiovascular disease (ASCVD) and Reynolds risk score (RRS) score. All 5,324 consecutive patients (aged 57 ± 8years, 76% male) who underwent CACS screening at the Cleveland Clinic as part of a primary prevention executive health between March 16 and October 21 were included. The 10-year ASCVD, RRS, and multiethnic study on subclinical atherosclerosis CACS (MESA-CACS) risk scores were calculated and categorized as <1, 1 to 4.99, 5 to 9.99, and ≥10%. Compared with ASCVD, using MESA-CACS resulted in a downgraded risk in 1,667 subjects (31%), whereas 738 (14%) had an upgrade in risk (total of 45% reclassification). Similarly, compared with RRS, using MESA-CACS resulted in an upgraded risk in 797 (15%) and a downgrade in 1,380 (26%) subjects (total of 41% reclassification). However, by further dividing by the distribution of the coronary calcification, ASCVD overestimates the risk only for patients with coronary artery calcium (CAC) in 0 or 1 coronary artery only, whereas MESA-CACS overestimates if the CAC was noted in ≥2 arteries. Similarly, RRS only overestimates the risk for patients with 0 CAC, whereas it underestimates the risk for patients with any CAC. In conclusion, the use of MESA-CACS, along with CAC distribution in primary prevention clinics, results in differential and significant reclassification of traditional scores when calculating the 10-years coronary vascular disease risk. Overall, RRS underestimates and ASCVD overestimates the cardiovascular disease risk compared with MESA-CACS.

The physio-biochemical characterization reflected different calcium utilization efficiency between the sensitive and tolerant peanut accessions under calcium deficiency.

Peanut yield in southern China is usually limited by calcium deficiency in soil. Most previous studies have found that small-seed varieties showed higher tolerance than large-seed varieties (e.g. Virginia type) under calcium deficiency, however, our preliminary research found that sensitive varieties also existed in small-seed counterparts. Few studies have been conducted to characterize low-calcium tolerance among small-seed germplasms with genetic diversity, and the differences in physiological characteristics between sensitive and tolerant varieties has not been reported yet. Thus, in order to better understand such differences, the current study firstly collected and characterized a diversity germplasm panel consisting of 50 small-seed peanut genotypes via a 2-year field trial, followed by the physiological characterization in sensitive (HN032) and tolerant (HN035) peanut genotypes under calcium deficiency. As a result, the adverse effects brought by calcium deficiency on calcium uptake and distribution in HN032 was much larger than HN035. In details, calcium uptake in the aboveground part (leaves and stems) was reduced by 16.17% and 33.66%, while in the underground part (roots and pods), it was reduced by 13.69% and 68.09% under calcium deficiency for HN035 and HN032, respectively; The calcium distribution rate in the pods of HN035 was 2.74 times higher than HN032. The utilization efficiency of calcium in the pods of HN035 was 1.68 and 1.37 times than that of HN032 under calcium deficiency and sufficiency, respectively. In addition, under calcium deficiency conditions, the activities of antioxidant enzymes SOD, POD, and CAT, as well as the MDA content, were significantly increased in the leaves of HN032, peanut yield was significantly reduced by 22.75%. However, there were no significant changes in the activities of antioxidant enzymes, MDA content, and peanut yield in HN035. Therefore, higher calcium absorption and utilization efficiency may be the key factors maintaining peanut yield in calcium-deficient conditions for tolerant genotypes. This study lays a solid foundation for selecting low-calcium tolerant varieties in future peanut breeding.

Peripheral arterial disease treatment planning using noninvasive and invasive imaging methods

With the growing prevalence and mortality of peripheral arterial disease, preoperative assessment, risk stratification, and determining the correct indication for endovascular and open surgical procedures are essential for therapeutic decision-making. The effectiveness of interventional procedures is significantly influenced by the plaque composition and calcification pattern. Therefore, the identification of patients for whom endovascular treatment is the most appropriate therapeutic solution often remains a challenge. The most commonly used imaging techniques have their own limitations and do not provide findings detailed enough for specific, personalized treatment planning. Using state-of-the-art noninvasive and invasive imaging modalities, it is now possible to obtain a view, not only of the complex vascular anatomy and plaque burden of the lower extremity arterial system, but also of complex plaque structures and various pathologic calcium distribution patterns. In the future, as these latest advancements in diagnostic methods become more widespread, we will be able to obtain more accurate views of the plaque structure and anatomic complexity to guide optimal treatment planning and device selection. We reviewed the implications of the most recent invasive and noninvasive lower extremity imaging techniques and future directions.

Distribution of intracellular calcium during flow-induced migration of RAW264.7 cells

Cell migration is an important biological process regulated by mechanical stimulation, which leads to intracellular calcium response. Cell migration are dependent on the distribution and dynamic changes of intracellular calcium concentration. However, the temporal relation among mechanical stimulation, cell migration, and intracellular calcium distribution remains unclear. In this study, unidirectional flow and oscillatory flow were applied on osteoclast precursor RAW264.7 cells. The parameters of cell migration under fluid flow and intracellular calcium distribution along the migration or flow direction were calculated. Experimental results suggest the cells to adjust the [Ca2+]i distribution in the migration direction is independent of flow application or the reverse of flow direction, but the [Ca2+]i distribution in the flow direction is determined by the [Ca2+]i distribution-adjusting ability of cells and flow stimulation. Blocking calcium signaling pathways, namely, mechanosensitive cation-selective channels, phospholipase C, and endoplasmic reticulum, and removing extracellular calcium inhibited cell migration along the flow direction and the gradient distribution of intracellular calcium. This study provided insights into the mechanism of flow-induced cell migration and quantitative data for the recruitment of osteoclast precursors targeting the location of bone resorption.

In vitro laser scanning confocal microscopy and unsupervised segmentation: Quantification of cytosolic calcium and RNA distribution in hypoxic neurons.

The mimicry of neurodegenerative diseases in vitro can be observed through the induction of chronic hypoxia, and the impact of this stress is monitored using multiplexed imaging techniques. While laser scanning confocal microscopy (LSCM) is a valuable tool for observing single neurons under degenerative conditions, accurately quantifying RNA distribution and cell size by deep learning tools remains challenging due to the lack of annotated training datasets. To address this, we propose a framework that combines 3D tracking of RNA distribution and cell size identification using unsupervised image segmentation. Additionally, we quantified the calcium level in neurons using fluorescent microscopy using unsupervised image segmentation. First, we performed imaging of neuronal morphology using differential interference contrast (DIC) optics and RNA/calcium level imaging using fluorescent microscopy. Next, we performed k-means clustering-based cell segmentation. The results show that our framework can distinguish between distinct neuronal states under control and chronic hypoxic conditions. The analysis reveals that hypoxia induces a significant increase in cytosolic calcium level, reduction in neuron diameter, and alterations in RNA distribution.Clinical Relevance- The proposed framework is crucial to study the neurodegeneration process and evaluating the efficacy of neuroprotective drugs through image analysis.

Mitochondria-Endoplasmic Reticulum Contact Sites Dynamics and Calcium Homeostasis Are Differentially Disrupted in PINK1-PD or PRKN-PD Neurons.

It is generally believed that the pathogenesis of PINK1/parkin-related Parkinson's disease (PD) is due to a disturbance in mitochondrial quality control. However, recent studies have found that PINK1 and Parkin play a significant role in mitochondrial calcium homeostasis and are involved in the regulation of mitochondria-endoplasmic reticulum contact sites (MERCSs). The aim of our study was to perform an in-depth analysis of the role of MERCSs and impaired calcium homeostasis in PINK1/Parkin-linked PD. In our study, we used induced pluripotent stem cell-derived dopaminergic neurons from patients with PD with loss-of-function mutations in PINK1 or PRKN. We employed a split-GFP-based contact site sensor in combination with the calcium-sensitive dye Rhod-2 AM and applied Airyscan live-cell super-resolution microscopy to determine how MERCSs are involved in the regulation of mitochondrial calcium homeostasis. Our results showed that thapsigargin-induced calcium stress leads to an increase of the abundance of narrow MERCSs in wild-type neurons. Intriguingly, calcium levels at the MERCSs remained stable, whereas the increased net calcium influx resulted in elevated mitochondrial calcium levels. However, PINK1-PD or PRKN-PD neurons showed an increased abundance of MERCSs at baseline, accompanied by an inability to further increase MERCSs upon thapsigargin-induced calcium stress. Consequently, calcium distribution at MERCSs and within mitochondria was disrupted. Our results demonstrated how the endoplasmic reticulum and mitochondria work together to cope with calcium stress in wild-type neurons. In addition, our results suggests that PRKN deficiency affects the dynamics and composition of MERCSs differently from PINK1 deficiency, resulting in differentially affected calcium homeostasis. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

La importancia de la TCMD en la evaluación de los factores de riesgo antes del procedimiento TAVI y de sus complicaciones

Transcatheter aortic valve implantation (TAVI) is the alternative to surgical valve replacement, expanding its indications in the latest guidelines. Multidetector CT (MDCT) is essential in patient selection and detection of complications. Vascular complications are frequent, so it is important to analyze the anatomy of the vessels before the procedure. Regarding annular ruptures and ventricular perforations, the volume and distribution of calcium and the ventricular diameter play an important role. Finally, valve migration is a rare complication that can occur both during and after TAVI. Proper planning of the MDCT procedure reduces the risk of complications and gives the interventional cardiologist security both before and during the procedure.

Vessel Distribution Of Coronary Artery Calcium From Gated CT And Low-dose Ungated CT Imaging Does Not Improve The Prediction Of MACE In Patients Referred For SPECT

Vessel Distribution Of Coronary Artery Calcium From Gated CT And Low-dose Ungated CT Imaging Does Not Improve The Prediction Of MACE In Patients Referred For SPECT