Close Negative Correlation Research Articles

Sorption of Cu by chernozems in southern Russia

The adsorption of Cu2+ by chernozems and parent rocks in Rostov region has been studied under laboratory conditions. It is shown that the adsorption isotherms are described by the Langmuir equation. The Langmuir equation parameters (KL and C∞) have been calculated for all of the studied samples. It is shown that the values of C∞ are in close negative correlation with the values of cation exchange capacity (r=−0.88 at P=0.95). A close correlation is revealed between the KL values and the content of clay (r=0.78), as well as between KL and the content of silt in chernozem haplic and chernozems calcic of different textures (r=0.80). An even closer correlation exists between these parameters in separate size fractions of chernozems calcic (r=0.89 for clay and r=0.91 for the silt fraction). However, no significant correlation exists between the C∞ and KL values and the contents of silt and clay in all samples. Therefore, a conclusion is drawn about the effect of the sample composition, including organic matter, on the adsorption of Cu2+ by the objects studied. Mechanisms for the acidification of equilibrium solutions during the adsorption of Cu2+ by soils and the misbalance between the adsorbed Cu2+ cations and the exchangeable cations displaced into the solution are discussed. XANES and EXAFS analysis indicates a possibility for the formation of chelate Cu2+ complexes with humic acids and the substitution of Al3+ in octahedral positions by Cu2+ during the interactions with clay minerals.

The Effect of Lumbar Spinal Muscle on Spinal Sagittal Alignment: Evaluating Muscle Quantity and Quality.

The majority of earlier studies of the parameters of sagittal balance did not consider the influence of spinal muscles on spinal sagittal alignment. To analyze the relationship between the paraspinal muscle (quantity and quality) and sagittal alignment in elderly patients. We reviewed 50 full-spine lateral standing radiographs and lumbar magnetic resonance images of elderly patients at a single center. The radiographic parameters examined were thoracic kyphosis, lumbar lordosis (LL), sagittal vertical axis, pelvic tilt, sacral slope, and pelvic incidence (PI). The lumbar muscularity (LM; quantity) and fatty degeneration ratio (FD; quality) in the paraspinal muscle were measured at the L3 level on magnetic resonance images. The relationships between the parameters, LM, and FD were analyzed with the Pearson correlation coefficient and multiple linear regression. Pearson analysis demonstrated that the FD had significant correlations with age (r = 0.393), thoracic kyphosis (r = -0.559), pelvic tilt (r = 0.430), sagittal vertical axis (r = 0.488), and PI - LL (r = 0.479, P < .05), and a close negative correlation was found between the FD and LL (r = -0.505, P < .01). The LM had significant correlations with the LL (r = 0.342) and PI - LL (r = -0.283, P < .05). Regression models that controlled for confounding factors such as body mass index confirmed the correlations between the above parameters and FD (P < .05). The quality of the paraspinal muscle could be one of the various factors that influence sagittal balance. BMI, body mass indexCSA, cross-sectional areaFD, fatty degeneration ratioLL, lumbar lordosisLM, lumbar muscularityPI, pelvic incidencePT, pelvic tiltSC, subcutaneous fatSS, sacral slopeSVA, sagittal vertical axisTK, thoracic kyphosisVB, vertebral body.

Rendimento de forragem e morfogênese de Brachiaria brizantha cv. Marandu sob níveis de desfolhação nos cerrados de Roraima

The effect of defoliation levels (10, 15, 20, 25 and 30 cm above soil level) on dry matter (DM) yield and morphogenetic and structural characteristics of Brachiaria brizantha cv. Maranduwas evaluated under field conditions in Roraima´s savannas. The effects of defoliation levels on the DM yields, number of leaves/plant, medium blade length, leaf area index, leaf appearance and elongation rates were quadratics and maximum values recorded with cutting at 23.1; 18.6; 26.3; 24.1; 14.8 and 21.3 cm above soil level, respectively. The population tiller density was inversely proportional to the level of defoliation, while the opposite occurred for to leaf senescence rate. Apical meristem removing percentage was higher with increasing defoliation level. Aftermath regrowth showed close negative correlation with defoliation level.

Decreased MIZ1 Expression in Severe Experimental Acute Pancreatitis: A Rat Study.

We tested our hypothesis that Myc-interacting zinc finger protein 1 (MIZ1), a cell cycle regulator, suppressed inflammation, and therefore, represented a useful prognostic marker in patients with acute necrotizing pancreatitis (ANP) complicated by acute lung injury. Sprague-Dawley rats were randomly divided into control and ANP groups at different time points. The MIZ1 protein expression was measured by Western blot and ELISA, and confirmed using immunohistochemistry. The severity of pancreatic and lung injury was evaluated by the injury score and wet/dry weight ratio. The severity of disease was evaluated by serum C-reactive protein (CRP). The MPO activity of lung tissue amylase levels and the degree of inflammation were evaluated by serum tumor necrosis factor (TNF)-α and interleukin (IL)-6 expression. The risk due to multiple factors was investigated by relationship analysis. The serum levels of CRP, amylase, TNF-α, and IL-6 were gradually increased at 6, 24, and 48 h in ANP when compared with the control rats. The MIZ1 expressions were greatly decreased in ANP rats, especially at 24 h. Statistical analysis showed that there were time-dependent differences in ANP rats when compared with control rats (6 vs. 24 or 48 h, P < 0.01). MIZ1 showed close negative correlation with the degree of pancreatic and lung injury, serum amylase, CRP, TNF-α, and IL-6 (P < 0.01, respectively). The decreasing MIZ1 expression was closely correlated with inflammatory response, and development of ANP. Decreasing MIZ1 levels indicate a risk for ANP.

Mixed model approach for IBD-based QTL mapping in a complex oil palm pedigree.

BackgroundElaeis guineensis is the world’s leading source of vegetable oil, and the demand is still increasing. Oil palm breeding would benefit from marker-assisted selection but genetic studies are scarce and inconclusive. This study aims to identify genetic bases of oil palm production using a pedigree-based approach that is innovative in plant genetics.ResultsA quantitative trait locus (QTL) mapping approach involving two-step variance component analysis was employed using phenotypic data on 30852 palms from crosses between more than 300 genotyped parents of two heterotic groups. Genome scans were performed at parental level by modeling QTL effects as random terms in linear mixed models with identity-by-descent (IBD) kinship matrices. Eighteen QTL regions controlling production traits were identified among a large genetically diversified sample from breeding program. QTL patterns depended on the genetic origin, with only one region shared between heterotic groups. Contrasting effects of QTLs on bunch number and weights reflected the close negative correlation between the two traits.ConclusionsThe pedigree-based approach using data from ongoing breeding programs is a powerful, relevant and economic approach to map QTLs. Genetic determinisms contributing to heterotic effects have been identified and provide valuable information for orienting oil palm breeding strategies.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1985-3) contains supplementary material, which is available to authorized users.

Produção de forragem, composição química e morfogênese de Brachiaria brizantha cv. Marandu em diferentes idades de corte

The effects of plant age (14, 21, 28, 35 and 42 days) on dry matter (DM) yield, morphogenetic characteristics and regrowth of Brachiariabrizantha cv. Marandu were evaluated in a cutting trial carried out at Vilhena, Rondônia. The experiment was conducted in a clayey Red-Yellow Latosol with low fertility. DM yields and the leaf area index (LAI) increased consistently with growth stage, however, nitrogen, phosphorus, calcium, magnesium and potassium contents, absolute and relative growth rates, and leaf elongation rate decreased as plant age. Maximum DM yield and LAI were obtained, respectively, at 38.6 and 37.8 days. Apical meristem removing percentage increased with plant age. Aftermath regrowth showed close negative correlation with survival of apical meristems. These data suggest that grazing or cutting at 35 to 42 days were optimal for obtain maximum yields of rich forage and better pasture regrowth.

Abnormal intrinsic brain activity patterns in leukoaraiosis with and without cognitive impairment

The amplitude of low frequency fluctuations (ALFF) from resting-state functional MRI (rs-fMRI) signals can be used to detect intrinsic spontaneous brain activity and provide valuable insights into the pathomechanism of neural disease. In this study, we recruited 56 patients who had been diagnosed as having mild to severe leukoaraiosis. According to the neuropsychological tests, they were subdivided into a leukoaraiosis with cognitive impairment group (n=28) and a leukoaraiosis without cognitive impairment group (n=28). 28 volunteers were included as normal controls. We found that the three groups showed significant differences in ALFF in the brain regions of the right inferior occipital gyrus (IOG_R), left middle temporal gyrus (MTG_L), left precuneus (Pcu_L), right superior frontal gyrus (SFG_R) and right superior occipital gyrus (SOG_R). Compared with normal controls, the leukoaraiosis without cognitive impairment group exhibited significantly increased ALFF in the IOG_R, Pcu_L, SFG_R and SOG_R. While compared with leukoaraiosis without cognitive impairment group, the leukoaraiosis with cognitive impairment group showed significantly decreased ALFF in IOG_R, MTG_L, Pcu_L and SOG_R. A close negative correlation was found between the ALFF values of the MTG_L and the Montreal Cognitive Assessment (MoCA) scores. Our data demonstrate that white matter integrity and cognitive impairment are associated with different amplitude fluctuations of rs-fMRI signals. Leukoaraiosis is related to ALFF increases in IOG_R, Pcu_L, SFG_Orb_R and SOG_R. Decreased ALFF in MTG_L is characteristic of cognitive impairment and may aid in its early detection.

Linkages between climate, fire and vegetation in southwest China during the last 18.5ka based on a sedimentary record of black carbon and its isotopic composition

Abstract Fires are sensitive to climate changes, and in addition they have a major influence on the global carbon cycle, land-surface properties, and chemical composition of the atmosphere, which in turn can affect the climate system. Projecting the impacts of future climate changes on fire-mediated biogeochemical processes requires understanding of how various climatic factors influence regional fire regimes. However, long-term variations in fire activity and their controls are poorly known. In this study, we report the concentration of black carbon (BC) and its isotopic composition (δ13CBC) in an upland lake sediment core from southwest China in order to elucidate linkages between changes in fire regime, climate and vegetation over the past 18.5 ka. The results show that the sedimentary BC content recorded variations in fire activity and exhibits a close negative correlation with the amount of precipitation delivered by the Indian Summer Monsoon (ISM). During Heinrich Event 1(18.5–15.0 cal ka BP), the Younger Dryas (12.8–11.1 cal ka BP) and the mid- to late-Holocene, the weakening of the ISM led to greatly increased fire activity in southwest China. In the last 1.0 ka, the BC record may have been affected by human activity in the catchment which may have caused an increased influx of minerogenic material to the lake thereby diluting the sedimentary BC concentration. The general trend of changing vegetation compositions inferred from the δ13CBC values also tracks the variations of the ISM, suggesting a change from mixed C3/C4-plant ecosystems during the last glacial maximum to C3-plant-dominated forest during the Holocene. However, the abundance of C4 plants may be overestimated during the Bolling–Allerod warm interval and the early Holocene due to the fact that fires were probably limited to the savanna ecosystem in the valleys and low-lying basins.

Ocular hemodynamics in patients with rhegmatogenous retinal detachment

Aim. In case of retinal detachment atrophic processes lead to irreversible loss of functions within 4–6 days, it happens on underlying low ocular blood flow. In order to evaluate the degree of violation of regional hemodynamics in patients with retinal detachment two groups of patients were examined: the main group (52 patients with rhegmatogenous retinal detachment) and the control group (24 myopic patients with lattice form of peripheral chorioretinal dystrophy). Methods and results. Doppler and reography results had been compared, significant decrease of blood flow in patients with retinal detachment was found. No differences between affected and fellow eye in these patients, close negative correlation between the level of ocular blood flow and the degree of myopia in the control group. Conclusion. This demonstrates the feasibility of actions to improve regional blood flow in patients operated on for retinal detachment.

Global drivers effect in multi-annual variability of runoff

Abstract Changes in runoff parameters are very important for Slovakia, where stream-flow discharges, being supplied by precipitation and groundwater runoff, are preferentially influenced by climatic conditions. Therefore, teleconnections between runoff parameters, climate parameters and global atmospheric drivers such as North Atlantic Oscillation, Southern Pacific Oscillation, Quasi-biennial oscillation and solar activity were studied in the Nitra River Basin, Slovakia. Research was mostly based on records of 80 years (1931-2010) for discharges and baseflow, and 34 years for groundwater heads. Methods of autocorrelation, spectral analysis, cross-correlation and coherence function were used. Results of auto- correllograms for discharges, groundwater heads and base flow values showed a very distinct 11-year and 21-year periodicity. Spectrogram analysis documented the 11-year, 7.8-year, 3.6-year and 2.4-year periods in the discharge, precipitation and air temperature time series. The same cycles except of 11-years were also identified in the long-term series of the North Atlantic Oscillation and Southern Pacific Oscillation indices. The cycle from approximately 2.3 to 2.4-years is most likely connected with Quasi-biennial oscillation. The close negative correlation between the North Atlantic Oscillation winter index and the hydrological surface and groundwater parameters can be used for their prediction within the same year and also for one year in advance.

Comparison of soil parameters of the carbon and nitrogen cycles in a long-term fertilization field experiment

In a long-term fertilization field experiment set up in Debrecen-Látókép in 1983 on calcareous chernozem soil the changes in the chemical and microbiological characteristics related to the carbon and nitrogen cycles of the soil are shown and evaluated. The soil samples were taken in the 26th and 27th years of the experiment, (in 2009, 2010) from maize monoculture and tri-culture. In addition to the effects of fertilizer doses, correlations among soil chemical and microbiological properties were established; and the various ratios among some microbiological parameters were also evaluated.The elements of NPK fertilizers increased together with the doses, so the elements’ effect cannot be separated, the minimum factor is not identifiable.With increasing fertilizer doses, the soil pH decreased in both the mono- and triculture, parallelly there was a significant increase in hydrolytic acidity. A close negative correlation was proved between the pH(H2O) and hydrolytic acidity and pH(KCl) and hydrolytic acidity. An increased soil nutrient content was recorded in each NPK treatment, the available phosphorus and nitrate content increased in a higher proportion than that of potassium.Among the measured parameters of the carbon and nitrogen cycles fertilization had a positive influence on the organic carbon (OC), organic nitrogen (ON), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) contents, the number of cellulose decomposing and nitrifying bacteria, the nitrate exploration and CO2-production, while it mainly had negative effects on the investigated enzymes (saccharase and urease) activity.Evaluating the ratios among the measured parameters, fertilization seems to have promoted the increase in nitrogen-containing organic compounds, because the OC/ON and MBC/MBN ratios decreased due to the effect of different doses of NPK fertilizers in both cultures.

Mapping of QTL for the seed storage proteins cruciferin and napin in a winter oilseed rape doubled haploid population and their inheritance in relation to other seed traits

Cruciferin (cru) and napin (nap) were negatively correlated and the cru/nap ratio was closely negative correlated with glucosinolate content indicating a link between the two biosynthetic pathways. Canola-type oilseed rape (Brassica napus L.) is an economically important oilseed crop in temperate zones. Apart from the oil, the canola protein shows potential as a value-added food and nutraceutical ingredient. The two major storage protein groups occurring in oilseed rape are the 2 S napins and 12 S cruciferins. The aim of the present study was to analyse the genetic variation and the inheritance of napin and cruciferin content of the seed protein in the winter oilseed rape doubled haploid population Express 617 × R53 and to determine correlations to other seed traits. Seed samples were obtained from field experiments performed in 2 years at two locations with two replicates in Germany. A previously developed molecular marker map of the DH population was used to map quantitative trait loci (QTL) of the relevant traits. The results indicated highly significant effects of the year and the genotype on napin and cruciferin content as well as on the ratio of cruciferin to napin. Heritabilities were comparatively high with 0.79 for napin and 0.77 for cruciferin. Napin and cruciferin showed a significant negative correlation (-0.36**) and a close negative correlation of the cru/nap ratio to glucosinolate content was observed (-0.81**). Three QTL for napin and two QTL for cruciferin were detected, together explaining 47 and 35 % of the phenotypic variance. A major QTL for glucosinolate content was detected on linkage group N19 whose confidence interval overlapped with QTL for napin and cruciferin content. Results indicate a relationship between seed protein composition and glucosinolate content.

A ∼200 ka pollen record from Okinawa Trough: Paleoenvironment reconstruction of glacial-interglacial cycles

Pollen analysis was carried out on the Core MD982194 of 29.78 m retrieved from the Middle Okinawa Trough which was dated as old as ~200 ka BP. The results revealed that pollen assemblages mainly presented an alternation of coniferous and herb pollen. The coniferous saccate pollen, principally Pinus and Tsuga, predominated in most parts of the core, especially highlighted in the interstadial stages including MIS 1,3, 5 and MIS7, whereas the herb pollen significantly increased in the gla- cial periods. Thus the pollen flora and their percentages showed the sensitive changes under the influence of ice volume during the glacial and interglacial periods. Our record from this core has first documented that the percentage of Cyperaceae was ex- tremely high in the glacial stages with a notable increase in Artemisia, Gramineae, Asteraceae, Chenopodiaceae, and freshwa- ter algae, which can be used as a proxy for sea-level change at the study site because of their close negative correlation of the orbital-scale changes in sea level. The distance between the continental coastline and the Okinawa Trough has deeply short- ened due to the sea-level drop in the LGM. As a result, the sediment materials from Yangtze River were extensively deposited on the flat, exposed continental shelf owing to the rapid decline of river flow speed, leading to that pollen grains from Okinawa Trough are derived mainly from the flat coastal vegetation of exposed continental shelf at glacial stages. Changes of pollen as- semblage were consistent with the variation of temperature and humidity, which showed that the percentage of arboreal pollen was highly augmented at MIS 7, 5 and MIS 1, corresponding to the strengthening of the East Asian summer monsoon and in- creasing of rainfall. Moreover, the peak of Pinus percentage in MIS 5.3, 5.1 and MIS 3.3 may be closely linked by orbital and sub-orbital cycles of solar radiation and monsoonal variability. The present study of core MD981294 implied lower tempera- ture and precipitation during the lowest sea-level stage (LGM), and more visibly testified that the vegetation of the flat plain on the exposed continental shelf was dominated by intrazonal communities such as halophyte grasslands and freshwater wetlands instead of zonal steppe or semi-arid desert. All above evidence demonstrated that the fundamental changes of pollen assem- blage and their origins in Okinawa Trough since ~200 ka BP were affected by combine factors including the coastline position and climate fluctuation. Moreover, the substantial shortening of distance between shoreline and the Okinawa Trough driven by orbital insolation cycles was clearly indicated by the pollen spectra, whereas the source-area climate signal of the pollen record was largely weakened.

Multi-center pragmatic studies evaluating the time indicator of cardiac perfusion reserve

Background: Since the greater part of coronary blood flow takes place during the diastolic phase of each cardiac cycle, a time indicator of myocardial perfusion reserve, the ratio of diastolic to systolic duration (D/S ratio), was presented. The objective of this study was to evaluate the accuracy and precision, the biological implication, and the applications of D/S ratio. Methods: Multi-center pragmatic studies evaluating the time indicator of cardiac perfusion reserve were performed. Related experiments, clinical trials, and surveys were conducted at 5 centers. Results: The results showed that the measurement of D/S ratio is both accurate and precise; the mean values of D/S of all of the 3 species studied (human, rabbit, and rat) were greater than 1. These application studies on D/S ratio showed that a close negative correlation existed between D/S ratio and New York Heart Association Functional Classification (NYHA FC) (r = –0.659, p pregnant women with pre-eclampsia and either normal pregnant women or non-pregnant women were significant (p Conclusions: D/S ratio has important biological implication, which is a safe, easy, reliable, and effective indicator, can be used to evaluate fitness levels, served as a pathophysiological marker for screening of cardiovascular disease (CVD), for predicting risk of cardiac events, and for evaluating the severity and prognosis of CVD.

One-Time Injection of Parathyrin Increases Glucose Tolerance

One-time injection of domestic preparation of bull parathyrin—parathyreoidin (1 U/100g body weight, intramuscular) leads to a significant decrease of the blood glucose level and an increase of the serum calcium level in rats. There is a close negative correlation established between glucose and calcium level (r = ?0.813, P > 0.02). The calcium laktat load (9 mg) per os induces the same changes. There is a functional negative correlation established between glucose levels and total calcium content (r = ?0.997, P 0.01). It proves that the decrease of the blood glucose level under parathyrin injection is connected with hypercalcaemia. Parathyrin causes the reduction of the dynamics of hyperglycemia under the glucose load per os (30% solution, 1 ml/100g), i.e. parathyrin increases glucose tolerance. Glucose consumption by muscle (diaphragm) and adipose (epididymal) tissues in vivo and in vitro does not alter under parathyrin and it does not affect the stimulating effect of insulin on the process. The combinative effect of parathyrin and calcium channel blockers—isoptin (5 mg/kg, intraperitoneal) or nifedipin (1 mg/kg, intraperitoneal) reveals more intensive and lasting decrease of the blood glucose level in comparison with only parathyrin effect and more reduction of the dynamics of hyperglycemia under the glucose load. Thus, parathyrin decreases the blood glucose level, increases glucose tolerance and does not effect insulin resistance.

Cerebral magnetic resonance elastography in supranuclear palsy and idiopathic Parkinson's disease

Detection and discrimination of neurodegenerative Parkinson syndromes are challenging clinical tasks and the use of standard T1- and T2-weighted cerebral magnetic resonance (MR) imaging is limited to exclude symptomatic Parkinsonism. We used a quantitative structural MR-based technique, MR-elastography (MRE), to assess viscoelastic properties of the brain, providing insights into altered tissue architecture in neurodegenerative diseases on a macroscopic level. We measured single-slice multifrequency MRE (MMRE) and three-dimensional MRE (3DMRE) in two neurodegenerative disorders with overlapping clinical presentation but different neuropathology — progressive supranuclear palsy (PSP: N = 16) and idiopathic Parkinson's disease (PD: N = 18) as well as in controls (N = 18). In PSP, both MMRE (Δμ = − 28.8%, Δα = − 4.9%) and 3DMRE (Δ|G*|: − 10.6%, Δφ: − 34.6%) were significantly reduced compared to controls, with a pronounced reduction within the lentiform nucleus (Δμ = − 34.6%, Δα = − 8.1%; Δ|G*|: − 7.8%, Δφ: − 44.8%). MRE in PD showed a comparable pattern, but overall reduction in brain elasticity was less severe reaching significance only in the lentiform nucleus (Δμ n.s., Δα = − 7.4%; Δ|G*|: − 6.9%, Δφ: n.s.). Beyond that, patients showed a close negative correlation between MRE constants and clinical severity. Our data indicate that brain viscoelasticity in PSP and PD is differently affected by the underlying neurodegeneration; whereas in PSP all MRE constants are reduced and changes in brain softness (reduced μ and |G*|) predominate those of viscosity (α and φ) in PD.

Usefulness of Atrial Deformation Analysis to Predict Left Atrial Fibrosis and Endocardial Thickness in Patients Undergoing Mitral Valve Operations for Severe Mitral Regurgitation Secondary to Mitral Valve Prolapse

In patients with severe mitral regurgitation (MR) referred for cardiac surgery, left atrial (LA) remodeling and enlargement are accompanied by mechanical stress, mediated cellular hypertrophy, and interstitial fibrosis that finally lead to LA failure. Speckle tracking echocardiography is a novel non-Doppler-based method that allows an objective quantification of LA myocardial deformation, becoming useful for LA functional analysis. We conducted a study to evaluate the relation between the traditional and novel atrial indexes and the extent of ultrastructural alterations, obtained from patients with severe MR who were undergoing surgical correction of the valvular disease. The study population included 46 patients with severe MR, referred to our echocardiographic laboratory for a diagnostic examination before cardiac surgery. The global peak atrial longitudinal strain (PALS) was measured in all subjects by averaging all atrial segments. LA tissue samples were obtained from all patients. Masson's trichrome staining was performed to assess the extent of the fibrosis. The LA endocardial thickness was measured. A close negative correlation between the global PALS and grade of LA myocardial fibrosis was found (r=-0.82, p <0.0001), with poorer correlations for the LA indexed volume (r= 0.51, p= 0.01), LA ejection fraction (r= 0.61, p= 0.005), and E/E' ratio (0.14, p= NS). Of these indexes, global PALS showed the best diagnostic accuracy to detect LA fibrosis (area under the curve 0.89), and it appears to be a strong and independent predictor of LA fibrosis. Furthermore, we also demonstrated an inverse correlation between the global PALS and LA endocardial thickness (r=-0.66, p= 0.0001). In conclusion, in patients with severe MR referred for cardiac surgery, impairment of LA longitudinal deformation, as assessed by the global PALS, correlated strongly with the extent of LA fibrosis and remodeling.

Right Ventricular Longitudinal Strain and Right Ventricular Stroke Work Index in Patients With Severe Heart Failure: Left Ventricular Assist Device Suitability for Transplant Candidates

BackgroundRight ventricular (RV) systolic function has a critical role in determining the clinical outcome and the success of using left ventricular assist devices in patients with refractory heart failure. RV deformation analysis by speckle tracking echocardiography (STE) has recently allowed the analysis of RV longitudinal function. Using cardiac catheterization as the reference standard, this study aimed to explore the correlation between RV longitudinal function by STE and RV stroke work index (RVSWI) among patients referred for cardiac transplantation. MethodsRight heart catheterization and transthoracic echo-Doppler were simultaneously performed in 47 patients referred for cardiac transplant assessment due to refractory heart failure (ejection fraction 25.1 ± 4.5%). Thermodilution RV stroke volume and invasive pulmonary pressures were used to obtain RVSWI. RV longitudinal strain (RVLS) by STE was assessed averaging RV free-wall segments (free-wall RVLS). We also calculated. Tricuspid S' and tricuspid annular plane systolic excursion (TAPSE). ResultsNo significant correlation was observed for TAPSE on tricuspid S' with RV stroke volume (r = 0.14 and r = 0.06, respectively). A close negative correlation between free-wall RVLS and RVSWI was found (r = −0.82; P < .0001). Furthermore, free-wall RVLS showed the highest diagnostic accuracy (area under the curve of 0.90) with good sensitivity and specificity of 95% and 91%, respectively, to predict depressed RVSWI using a cutoff value less than −11.8%. ConclusionsAmong patients referred for heart transplantation, TAPSE and tricuspid S' did not correlate with invasively obtained RVSWI. RV longitudinal deformation analysis by STE correlated with RVSWI, providing a better estimate of RV systolic performance.

Effect of cytoskeletal elastic properties on the mechanoelectrical transduction in excitable cells

This paper addresses the possible mechanism of stretch on cell electrochemical potential change, based on the physicochemical properties of cytoskeletal network. Synthetic polyelectrolyte gel was used as an experimental model of the cytoskeleton. Gel samples with different density of network cross linking were studied. Triangular axial deformations of samples were applied. Simultaneously, the electrochemical (Donnan) potential of the gel was measured between a micropipette electrode pinned into the swollen gel, and a reference electrode in the outer solution. We found that axial deformation shifts the gel potential toward depolarization. The extent of gel depolarization showed a close negative correlation with the Young modulus of the gel. We suggest that the underlying mechanism is likely to be a universal process of counterion adsorption on charged polymer filaments due to the decrease of distance between polymer filaments owing to gel elongation.

Calcium Channel Blockers Inhibit the Hyperglycemic Effect of Calcitonin

We studied the effect of Russian preparation of porcine calcitonin (calcitrin, 1 U/100 g) and blockers of Ca(2+) channels nifedipine (1 mg/kg, blocker of chemosensitive Ca(2+) channels) and isoptin (5 mg/kg, blocker of voltage-dependent Ca(2+) channels) on glucose metabolism. Calcitonin produced a pronounced hyperglycemic effect in rats. A close negative correlation was found between glucose level and total calcium content. Injection of calcitonin reduced glucose tolerance in rats. Isoptin and nifedipine reduced plasma calcium level and did not affect significantly the blood glucose levels, did not change the pattern of alimentary hyperglycemia in response to glucose load, completely abolished the hyperglycemic effect of calcitonin, and prevented calcitonin-induced impairment of glucose tolerance.