Dilation Index Research Articles

A numerical study on pulsatile non-Newtonian hemodynamics in double-fusiform abdominal aortic aneurysms

Abdominal Aortic Aneurysm (AAA) is a multi-factorial pathological event that occurs in the human body. In the present work, the hemodynamics pertaining to AAA are numerically analyzed. To comprehend the blood flow phenomenon in a double-fusiform aneurysm, axisymmetric simulations of pulsatile non-Newtonian blood flow are performed using OpenFOAM. The Carreau–Yasuda model is used to evaluate the non-Newtonian behavior of blood. The Reynolds number and Womersley number are altered as per the physiologically applicable range to characterize the hemodynamics. The Dilatation Index is also varied to quantify the consequence of different enlargements of the abdominal aorta on the blood flow. Four hemodynamic indicators—time-averaged wall shear stress, Oscillatory Shear Index (OSI), Relative Residence Time (RRT), and vascular impedance—are used to identify several complications such as atherosclerosis, vascular inflammation, endothelial dysfunction, and hyperplasia. As the pulse rate increases, the chances of particle stagnation inside the aneurysm decrease due to lower RRT. Our results suggest that patients with hypoxia or bradycardia (low Womersley number) are more susceptible to atherosclerosis due to the high value of RRT. Thus, we recommend mild exercise for patients with AAA. After analyzing the hemodynamic indicators, % of area with RRT > 0.5 is identified as the critical parameter to propose a regime map. Low pulse rates are found to be critical at low flow rates, whereas high pulse rates are found to be critical with high flow rates. Furthermore, it is found that the severity increases as the size of the aneurysm increases.

Anti-Müllerian hormone and vascular dysfunction in women with chronic kidney disease.

Young women with chronic kidney disease (CKD) have disproportionately increased risk of cardiovascular mortality. Reduced anti‐Müllerian hormone (AMH) is linked to poor cardiovascular outcomes in the general population, but whether AMH is associated with increased cardiovascular risk in the high‐risk CKD population is unknown. This study examined the association between AMH and vascular function, validated markers of cardiovascular risk, in women with CKD. An exploratory cross‐sectional study was performed in 47 young women with CKD. Laboratory measurements of AMH were collected. Using standardized protocols, endothelial function was measured with brachial artery flow‐mediated dilation and hyperemic velocity time integral. Arterial stiffness was measured with aortic augmentation index and pulse wave velocity. Multivariate linear regression analyses were utilized to evaluate the association between AMH levels and each measure of vascular health. Forty women (36 ± 7 years) with non‐dialysis‐dependent CKD and 7 women (38 ± 6 years) with dialysis‐dependent CKD participated. AMH levels were inversely associated with age (p = 0.01) but not associated with eGFR (p = 0.59) or dialysis status (p = 0.97). AMH was associated with brachial artery flow‐mediated dilation (R 2 = 0.21 [p = 0.03]) and aortic augmentation index (R 2 = 0.20 [p = 0.04]) in the non‐dialysis‐dependent participants, and with aortic augmentation index in all participants (R 2 = 0.18 [p = 0.03]). No association between AMH and any measure of vascular function was demonstrated in the dialysis‐dependent participants. AMH levels are associated with impaired vascular function in young women with CKD and may be an important marker of future cardiovascular risk. Further investigation into this female‐specific cardiovascular risk factor is warranted in this high‐risk population.

Validity of flow-mediated dilation and reactive hyperemia index in assessing the risk of coronary artery disease based on the new definition by the Japan Society for Vascular Failure

Background: Flow-mediated dilation (FMD) measurement and reactive hyperemia-peripheral arterial tonometry (RH-PAT) are established methods for assessing vascular endothelial function. Recently, the Japan Society for Vascular Failure proposed a new definition for the values of FMD (≥7.0%, normal; 7.0%> and ≥4.0%, borderline; 4.0%≥, abnormal) and reactive hyperemia index (RHI) measured using RH-PAT (≥2.10, normal; 2.10≥ and >1.67, borderline; 1.67≥, abnormal). This study aimed to assess the clinical significance of FMD and RHI in coronary artery disease (CAD) based on the new definition. Methods: We performed simultaneous FMD and RH-PAT measurements in 131 patients undergoing coronary angiography for suspected CAD. The patients were divided into subgroups according to the normal, borderline, and abnormal values of FMD and RHI in the new definition. Results: No significant correlation was found between the FMD and RHI values in the overall patients. In the normal FMD/normal RHI, normal FMD/abnormal RHI, abnormal FMD/normal RHI, and abnormal FMD/abnormal RHI groups, the prevalence of multivessel CAD was 0%, 25%, 36%, and 56% (P=0.038), respectively. Furthermore, multivessel CAD was observed in 17% of patients in the borderline FMD/borderline RHI group, and the prevalence showed a significant difference among the normal FMD/normal RHI, borderline FMD/borderline RHI, and abnormal FMD/abnormal RHI groups (P=0.006). Multivariate logistic regression analysis showed that abnormal FMD/abnormal RHI was an independent predictor of multivessel CAD (odds ratio: 3.172, 95% confidence interval: 1.012-7.336, P=0.042). Conclusions: The evaluation of simultaneously measured FMD and RHI values based on the new definition would be advantageous for predicting the severity of CAD.

A Numerical Investigation into the Effect of Homogeneity on the Time-Dependent Behavior of Brittle Rock.

To investigate the brittle creep failure process of rock material, the time-dependent properties of brittle rocks under the impact of homogeneity are analyzed by the numerical simulation method, RFPA-Creep (2D). Deformation is more palpable for more homogeneous rock material under the uniaxial creep loading condition. At a low stress level, diffusion creep may occur and transition to dislocation creep with increasing applied stress. The law for increasing creep strain with the homogeneity index under a constant confined condition is similar to the uniaxial case, and dislocation creep tends to happen with increasing confining pressure for the same homogeneity index. The dilatancy index reaches its maximum at a high stress level when rock approaches failure, and the evolution of the dilatancy index with the homogeneity index under the same confining pressure is similar to the uniaxial case and is more marked than that under the unconfined condition. Both uniaxial and triaxial creep failure originate from the ductile damage accumulation inside rock. The dominant shear-type failure is exhibited by uniaxial creep and the conventional compression case presents the splitting-based failure mode. Under confining pressure, the creep failure pattern is prone to shear, which is more notable for the rock with higher homogeneity.

Reactive Hyperemia-Triggered Wrist Pulse Analysis for Early Monitoring of Young Men with High Atherosclerotic Risk.

The high prevalence of cardiovascular disease in young adults has raised significant concern regarding the early identification of risk factors to allow for timely intervention. This study aimed to identify young males at risk of atherosclerosis using a noninvasive instrument and an initial application percussion entropy analysis of the wrist pressure pulse (WPP). In total, 49 young males aged 18 to 28, without any known history of vascular disease, were recruited. Blood samples were obtained whereby a TC/HDL cutoff value of 4 was used to divide the young men into low-risk (Group 1, TC/HDL < 4, N = 32) and high-risk (Group 2, TC/HDL ≥ 4, N = 17) groups regarding atherosclerosis. The reactive hyperemia-triggered WPPs were measured using a modified air-pressure-sensing system (MAPSS). The dilation index (DI) of the endothelial function and percussion entropy index (PEI) of the heart rate variability (HRV) assessments, calculated using pragmatic signal-processing techniques, were compared between the two groups. The nonparametric Mann–Whitney U test showed that the DI and PEI of the two groups showed statistical differences (both p < 0.05). Not only could the MAPSS assess endothelial function and HRV in young males, but the results also showed that waist circumference and PEI may serve as indicators for the early identification of young males at risk of atherosclerosis.

Effect of particle shape on shear behaviour of aggregate-geogrid interface under different aperture ratios

ABSTRACT Effects of aggregate size and shape on monotonic shear behaviour of unreinforced and geogrid-reinforced aggregate interfaces were systematically investigated through direct shear tests. Five different grades of angular aggregates and five kinds of rounded aggregates with identical particle size distribution were selected as test materials. Experiment results revealed the coupling effects of particle shape and aperture ratio (AS/D50 ), defined as the ratio of geogrid aperture size (AS) to the average particle size of aggregate (D50 ), on the shear behaviour of the unreinforced and reinforced interfaces. The peak shear stress, shear displacements corresponding to peak shear stress and residual shear stress, as well as maximum dilation of aggregate–geogrid interfaces at each AS/D50 were greater than those of glass beads–geogrid interfaces. The largest interface shear strength coefficient of aggregate–geogrid interfaces was achieved at AS/D50 = 2.55, and the optimum reinforcement of glass beads–geogrid interfaces appeared at AS/D50 = 5.05. The shear strength decreased more after the peak when the value of AS/D50 was relatively small, and the post-peak strength reduction of aggregate–geogrid interfaces was more pronounced. A generalised stress-dilatancy relationship was proposed, which introduced a variable dilatancy index (ζ) that reflected the effects of aperture ratio and particle shape.

Effects of Continuous-Flow Left Ventricular Assist Device Therapy on Peripheral Vascular Function

The peripheral vascular effects of continuous-flow left ventricular assist device (CF-LVAD) implantation are still unclear. The aim of the current study was to determine peripheral vascular function before and after implantation of CF-LVAD in patients with end-stage heart failure (HF), and to compare this data to age- and sex-matched chronic heart failure with reduced ejection fraction (HFrEF) patients. Forty-three consecutive end-stage HF patients (New York Heart Association [NYHA] class III/IV; three women and 40 men; mean age 53 ± 11 years) who planned to receive CF-LVAD implantation comprised the LVAD patient population, and their clinical characteristics, preoperative and third postoperative month peripheral vascular function assessment data including flow-mediated dilation (FMD) and pulsatility index (PI) assessed by ultrasound Doppler in brachial artery were compared to age- and sex-matched chronic, stable HFrEF patients (NYHA class II; five women and 30 men; mean age 51 ± 10 years). After CF-LVAD implantation, median FMD decreased from 5.4 to 3.7% (p &lt; 0.001), and median PI decreased from 6.9 to 1.4 (p &lt; 0.001). In patients with end-stage HF before CF-LVAD implantation, FMD and PI were significantly lower compared to the chronic HFrEF patients (FMD: 5.4% ± 0.9% vs. 7.6% ± 1.1%; p &lt; 0.001, respectively) and (PI: 6.9 ± 1.3 vs. 7.4 ± 1.2; p = 0.023, respectively). The current study revealed impaired peripheral vascular function in the end-stage HF patients compared to stable HFrEF patients, and documented the deterioration of peripheral vascular function after CF-LVAD implantation. These results suggest that impaired peripheral vascular function in the CF-LVAD patients compared to preoperative assessment is a consequence of the nonpulsatile blood flow due to the continuous-flow mechanical support.

Quantitatively comparing weekly changes in retinal vascular characteristics of eyes eventually treated versus not treated for retinopathy of prematurity

To quantitatively compare retinal vascular characteristics over time in eyes eventually treated versus not treated for retinopathy of prematurity (ROP), using ROPtool analysis of narrow-field retinal images. This longitudinal study used prospectively collected narrow-field retinal images of infants screened for ROP, prior to treatment, if needed. Images were analyzed using a methodology that combines quadrant-level measures from several images of the same eye. For the longitudinal analysis, one examination per postmenstrual age (PMA) was included per eye. We compared the following ROPtool indices and their change per week between eyes eventually treated versus not treated for ROP: tortuosity index (TI), dilation index (DI), sum of adjusted indices (SAI), and tortuosity-weighted plus (TWP). Analysis was performed on three levels: eye (mean value/eye), quadrant (highest quadrant value/eye), and blood vessel (highest blood vessel value/eye). Of 832 examinations (99 infants), 745 images (89.5%) had 3-4 quadrants analyzable by ROPtool. On the eye level, ROPtool indices differed between eyes eventually treated versus not treated at PMA of 33-35 and 37weeks for TI, SAI, and TWP, and at PMA of 33-34 and 37weeks for DI (P≤0.0014), and change per week differed between eyes eventually treated versus not treated only for SAI at PMA of 32weeks (P<0.001). Quantitative analysis of retinal vascular characteristics using ROPtool can help predict eventual need for treatment for ROP as early as 32weeks PMA. ROPtool index values were more useful than change in these indices to predict eyes that would eventually need treatment for ROP.

Symmetric Spaces of Measurable Functions: Old and New Advances

The article is an extensive review in the theory of symmetric spaces of measurable functions. It contains a number of new (recent) and old (known) results in this field. For the most of the results, we give their proofs or exact references, where they can be found. The symmetric spaces under consideration are Banach (or quasi-Banach) latices of measurable functions equipped with symmetric (rearrangement invariant) norm (or quasinorm). We consider symmetric spaces E = E(Ω, Fμ, μ) ⊂ L0 (Ω, Fμ, μ) on general measure spaces (Ω, Fμ, μ), where the measures μ are assumed to be finite or infinite σ-finite and nonatomic, while there are no assumptions that (Ω, Fμ, μ) is separable or Lebesgue space. In the first section of the review, we describe main classes and basic properties of symmetric spaces, consider minimal, maximal, and associate spaces, the properties (A), (B), and (C), and Fatou’s property. The list of specific symmetric spaces we use includes Orlicz LΦ(Ω, Fμ, μ), Lorentz ΛW (Ω, Fμ, μ), Marcinkiewicz MV (Ω, Fμ, μ), and Orlicz-Lorentz LW,Φ (Ω, Fμ, μ) spaces, and, in particular, the spaces Lp (w), Mp(w), Lp,q, and L∞(U ). In the second section, we deal with the dilation (Boyd) indexes of symmetric spaces and some applications of classical Hardy-Littlewood operator H. One of the main problems here is: when H acts as a bounded operator on a given symmetric space E(Ω, Fμ, μ)? A spacial attention is paid to symmetric spaces, which have Hardy-Littlewood property (HLP) or weak Hardy-Littlewood property (WHLP). In the third section, we consider some interpolation theorems for the pair of spaces (L1 , L∞) including the classical Calderon-Mityagin theorem. As an application of general theory, we prove in the last section of review Ergodic Theorems for Cesaro averages of positive contractions in symmetric spaces. Studying various types of convergence, we are interested in Dominant Ergodic Theorem (DET ), Individual (Pointwise) Ergodic Theorem (IET ), Order Ergodic Theorem (OET ), and also Mean (Statistical) Ergodic Theorem (MET ).

Experimental Investigation on Deformation and Strength Behavior of Marble with the Complex Loading-Unloading Stress Path

The excavation of deep tunnel in rock mass undergoes complex loading and unloading stress paths, resulting in rib spalling, flaking, and even severe rockburst disasters. Based on the variation law of the stress path of the surrounding rock, laboratory tests of rock mechanics are designed, and the deformation and strength behavior of marble with different initial confining pressure and unloading rates are systematically studied. By introducing strain increment, the characteristic stress, and the dilatancy index, the rock’s dilatancy and brittleness under different unloading conditions are quantitatively analyzed. During unloading, the energy transformation mechanism of rock is described, and the law of deformation and failure is discussed based on characteristic energy. The rock failure strength fitting formula is given by applying the Mogi–Coulomb criterion and elastic strain energy criterion. The advantages of the elastic strain energy criterion are theoretically explained. This study shows that comprehensive consideration of the complex stress paths, confining pressure levels, and the loading-unloading rates of surrounding rock is an effective way to accurately study unloading rock characteristics. The results can provide theoretical basis for stability analysis of high-stress underground engineering.

Vascular Effects of ACE (Angiotensin-Converting Enzyme) Inhibitors and Statins in Adolescents With Type 1 Diabetes.

An increased albumin-creatinine ratio within the normal range can identify adolescents at higher risk of developing adverse cardio-renal outcomes as they progress into adulthood. Utilizing a parallel randomized controlled trial and observational cohort study, we characterized the progression of vascular phenotypes throughout this important period and investigated the effect of ACE (angiotensin-converting enzyme) inhibitors and statins in high-risk adolescents. Endothelial function (flow-mediated dilation and reactive hyperemia index) and arterial stiffness (carotid-femoral pulse wave velocity) were assessed in 158 high-risk participants recruited to a randomized, double-blind placebo-controlled 2×2 factorial trial (randomized, placebo-controlled trial) of ACE inhibitors and/or statins in adolescents with type 1 diabetes (AdDIT [Adolescent Type 1 Diabetes cardio-renal Intervention Trial]). Identical measures were also assessed in 215 lower-risk individuals recruited to a parallel observational study. In the randomized, placebo-controlled trial, high-risk patients randomized to ACE inhibitors had improved flow-mediated dilation after 2 to 4 years of follow-up (mean [95% CI]: 6.6% [6.0-7.2] versus 5.3% [4.7-5.9]; P=0.005), whereas no effect was observed following statin use (6.2% [5.5-6.8] versus 5.8% [5.1-6.4]; P=0.358). In the observational study, patients classed as high-risk based on albumin-creatinine ratio showed evidence of endothelial dysfunction at the end of follow-up (flow-mediated dilation=4.8% [3.8-5.9] versus 6.3% [5.8-6.7] for high-risk versus low-risk groups; P=0.015). Neither reactive hyperemia index nor pulse wave velocity were affected by either treatment (P>0.05 for both), but both were found to increase over the duration of follow-up (0.07 [0.03-0.12]; P=0.001 and 0.5 m/s [0.4-0.6]; P<0.001 for reactive hyperemia index and pulse wave velocity, respectively). ACE inhibitors improve endothelial function in high-risk adolescents as they transition through puberty. The longer-term protective effects of this intervention at this early age remain to be determined. Registration- URL: https://www.clinicaltrials.gov; Unique identifier NCT01581476.

CO2/CH4 Pure- and Mixed-Gas Dilation and Sorption in Thin (∼500 nm) and Ultrathin (∼50 nm) Polymers of Intrinsic Microporosity

In this work, we present (i) the dilation and refractive index variation associated with changes in film density and (ii) gas uptake of pure CO2 and CH4, as well as their equimolar mixture in thin ...

Effects of agalsidase-β administration on vascular function and blood pressure in familial Anderson–Fabry disease

Fabry is an X-linked disorder of glycosphingolipid metabolism that is caused by variants of the GLA gene that codes for α-galactosidase A, leading to lysosomal accumulation of globotriaosylceramide in many cell types. As a result, affected patients manifest with an increased risk of developing ischemic stroke, peripheral neuropathy, cardiac dysfunction, and chronic kidney disease. The protective effects of enzyme replacement therapy (ERT), the milestone in Fabry disease treatment, against globotriaosylceramide (GL-3) accumulation and Fabry disease progression are well known. However, the mechanism of action of ERT is not well understood. Since GL-3 also accumulates in the vascular endothelium, we investigated the effects of agalsidase-β, a recombinant human α-Gal enzyme approved for the treatment of Fabry disease. In this study, vascular function and blood pressure in four adult siblings affected by Fabry disease were evaluated upon agalsidase-β. In all patients, agalsidase-β infusion improves flow-mediated dilation and augmentation index. These changes occurred after the first infusion and were then maintained for the whole period of observation, i.e., 1 year, with more pronounced additional increments in flow-mediated dilation after the second agalsidase-β infusion. Blood pressure was also maintained at optimal levels in all of the patients for the whole period of observation. Our findings show that agalsidase-β administration can improve vascular function in patients suffering from Fabry disease. Changes in flow-mediated dilation and augmentation index persisted for the whole period of observation (1 year), thus suggesting that early substitutive therapy should be promoted in order to protect the cardiovascular system.

A unified monotonic model for sand based on modified hyperbolic equation and state-dependent dilatancy

Accurate prediction of the state-dependent shearing behaviors of sand in a rational way is a challenging task of the development of constitutive models. In the present study, a deformation type model is proposed based on a modified Duncan-Chang hyperbolic equation, which provides a simple and efficient way to characterize the stress–strain relationship. The hyperbolic equation is improved to tackle the limitations when predicting the strain-softening behavior of sand. By coupling with a flow rule, the volumetric response under a drained condition and excess pore pressure generation under an undrained condition can be modeled as well. An empirical state variable, known as the relative dilatancy index, is implemented in the modified hyperbolic equation and the flow rule to model the state-dependent shearing behaviors in a unified way. The flow rule evolves with the state of soil during shearing and provides realistic simulations of dilatancy-related response. The calibration process for dilatancy and hyperbolic equations is suggested. The model is validated by drained and undrained triaxial compression tests of two silica sand, showing a fairly good capability of unified modeling of the sand behaviors with a wide range of densities and stress levels.

Токсигенність штамів yersinia еnterocolitica, ізольованих з різних об’єктів

Токсигенність штамів yersinia еnterocolitica, ізольованих з різних об’єктів

Endothelial function improvement in patients with familial hypercholesterolemia receiving PCSK-9 inhibitors on top of maximally tolerated lipid lowering therapy

BackgroundTreatment with protein convertase subtilisin kexin type 9 inhibitors (PCSK-9i) reduced cholesterol levels and cardiovascular events in patients with hypercholesterolemia. We assessed changes in lipid profile, oxidation markers and endothelial function in patients with familial hypercholesterolemia (FH) after a 12-week treatment with a PCSK-9i. MethodsPatients with FH starting a treatment with PCSK-9i were included. Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), lipoprotein(a) (Lp(a)), small dense LDL (assessed by LDL score), 11-dehydro-thromboxane (11-TXB2), 8-isoprostaglandin-2alpha (8-iso-PGF2α), flow-mediated dilation (FMD) and reactive hyperaemia index (RHI) were evaluated before starting PCSK-9i treatment and after a 12-week treatment. ResultsTwenty-five subjects were enrolled (52% males, mean age 51.5 years). At the 12-week assessment, we observed a 38% median reduction in TC, 52% in LDL-C, 7% in Lp(a) and 46% in LDL score. In parallel, 11-TXB2 and 8-iso-PGF2α showed a reduction of 18% and 17%, respectively. FMD changed from 4.78% ± 2.27 at baseline to 10.6% ± 5.89 at 12 weeks (p < 0.001), with RHI changing from 2.37 ± 1.23 to 3.76 ± 1.36 (p < 0.001). A multivariate analysis showed that, after adjusting for potential confounders, change in LDL score was an independent predictor of changes in FMD (β = −0.846, p = 0.015) and in 8-iso-PGF2α (β = 0.778, p = 0.012). ConclusionsSmall dense LDL reduction (assessed by LDL score) is related to changes in oxidation markers and endothelial function in patients with FH treated with PCSK-9i.

Evaluation Of Inter-rater And Test-retest Reliability For Near-infrared Spectroscopy Reactive Hyperemia Measures

Near-Infrared spectroscopy (NIRS) is a non-invasive tool used to measure blood flow in peripheral tissues. More information on test-retest reliability and inter-rater agreement of NIRS-based reperfusion assessments is needed. PURPOSE: To assess inter-rater agreement for NIRS based data analysis, and evaluate the measurement’s reliability across days. METHODS: On three separate days, participants’ (N=15 males, 22± 2 yr,) reactive hyperemia was measured in the left gastrocnemius muscle using Continuous-Wave NIRS. A blood pressure cuff was placed proximal to the knee and inflated to occlude lower leg blood flow for 5 minutes. The cuff was rapidly deflated, and the blood flow responses were measured until values returned to baseline. Raw NIRS data were exported and analyzed in a custom-written routine in MATLAB by two individuals. The following NIRS parameters were selected:(1) the time for the O2Hb signal to reach 50% peak post-occlusion hyperemia (T1/2), (2) The O2Hb range used to normalize the NIRS signal; (3) the post peak-hyperemic O2Hb recovery slope, taken as an index of sustained microvascular dilation. Inter-rater agreement was assessed using Intraclass Correlation Coefficients (ICC), calculated using an absolute agreement two-way mixed effects model. 95% confidence intervals (CI) of ICCs are reported. Cronbach’s alpha was used to assess day to day reliability for each of the measures. RESULTS: The ICC data indicate that there is “good” to “excellent” agreement between NIRS analyzers as shown in table 1.The Cronbach’s alpha for raters 1 and 2 were: T1/2 (α =.89, α = .91), O2Hb (α =.95, α = .89), and post peak-hyperemic O2Hb recovery slope (α =.74, α = .83). CONCLUSION: Our data indicate multiple raters can be used to analyze NIRS based reperfusion measures with good agreement and that the method has sufficient test-retest reliability to use in experimental designs involving multiple laboratory visits.

Effect of radiation on endothelial functions in workers exposed to radiation.

OBJECTIVE Our aim is to determine whether radiation affects the endothelial function of hospital staff working in the radiation unit for diagnostic and therapeutic purposes. We have evaluated endothelial function with vascular imaging parameters such as flow-mediated dilatation (FMD) and aortic stiffness index (ASI). METHODS A total of 75 employees, 35 of whom are exposed to radiation due to their profession and 40 as the control group, were included in our single-centered study. Demographic data, FMD, aortic stiffness, and echocardiographic findings of the two groups were compared. RESULTS There were no significant differences in demographic data. Median FMD values tended to be lower in the radiation exposure group [7.89 (2.17-21.88) vs. 11.69 (5.13-27.27) p=0.09]. The FMD value was significantly lower in the catheter laboratory group than in the radiation-exposed (p=0.034) and control (p=0.012) groups. However, there was no statistically significant difference between the non-catheter lab radiation exposed group and the control group (p=0.804). In addition, there was no statistically significant difference in the ASI value between the groups (p=0.201). CONCLUSION We have found that FMD is decreased among hospital staff working in radiation-associated areas. This may be an early marker for radiation-induced endothelial dysfunction.

From short-term blood pressure variability to atherosclerosis: Relative roles of vascular stiffness and endothelial dysfunction.

Both arterial blood pressure (BP) average levels and short-term BP variability (BPV) relate to hypertension-mediated organ damage, in particular increased carotid artery intima-media thickness (IMT) and carotid-femoral pulse wave velocity (PWV). Endothelial dysfunction possibly mediates such damage. The authors aimed at further investigating such role in hypertensive patients. In 189 recently diagnosed, untreated hypertensive patients the authors evaluated, in a cross-sectional design, the relationships of BP average levels and short-term systolic (S) BPV (standard deviation of awake SBP or of 24-hour-weighted SBP) with IMT and PWV, and how much these relationships are explained by endothelial function parameters-brachial artery flow-mediated dilation (FMD) and digital reactive hyperemia index (RHI). Multivariable models assessed the strength of these relationships to derive a plausible pathogenetic sequence. Both average SBP values and our measures of SBPV were significantly related to IMT (24-hour mean SBP: r=.156, P=.034; 24-hour-weighted SBPV: r=.157, P=.033) and to PWV (24-hour mean SBP: r=.179, P=.015; 24-hour-weighted SBPV: r=.175; P=.018), but only poorly related to FMD or RHI (P>.05 for all). At univariable regression analysis, FMD and RHI were both related to IMT, (P<.001), but not to PWV. When FMD and RHI were added to average SBP and SBPV parameters in a multivariable model, both significantly (P<.005) contributed to predict IMT, but not PWV. Thus, endothelial dysfunction relates to IMT independently of BP parameters, but appears to play a minor role in the association between BP variability-related variables and arterial stiffening.

Relationship between vitamin D deficiency and premature atherosclerosis in an adolescents with type 1 DM through inflammatory IFN-γ

Vitamin D deficiency has been related to increased risk of myocardial infarction, stroke. Type 1 DM patients have a higher risk of atherosclerosis, which is the leading cause of death in most patients, and IFN-γ is a pro inflammatory cytokine, and type 1 DM is a chronic inflammation. In our study, we try to detect the premature atherosclerosis in adolescents with type 1 DM who have vitamin D deficiency through inflammatory IFN-γ. The study is a case control with 31 diabetic children aged 6 to 18 years as a case group, and control group 35 healthy children aged 10-18 years. We analysis the vitamin D, IFN- and ,HbA1c, and using Doppler US for cIMT of common carotid artery(CCA), and flow mediated dilation index(FMD%) of the brachial artery. And analysis the data through SPSS version16.0. Type 1 DM group have higher levels of IFN-γ (p-0.005) and cIMT (p-0.01.) and both were significant, while the correlation effect of vitamin D deficiency and IFN-γ on both cIMT and FMD% were (p-0.294) and (p-0.270) (p-0.794)and (p-0.894) respectively and both insignificant, and correlation effect of HbA1c on cIMT was significant with (p-0.002), and correlation effect of HbA1c on FMD% was insignificant with (p-0.222). We concluded that there is significantly higher of IFN-γ in type 1 DM, also a significant correlation effect of HbA1c on cIMT, and no relationship between vitamin D deficiency and premature atherosclerosis in an adolescents with type 1 DM through inflammatory IFN-γ.