Vessel Rings Research Articles

Different patterns of inter-annual variability in mean vessel area and tree-ring widths of beech from provenance trials in Slovenia and Hungary

Key messageStudied beech provenances showed different patterns of inter-annual variability in mean vessel area and ring widths, indicating influence of intraspecific variability and diverse environment on hydraulic conductivity and carbon storage potential.International provenance trials of ecologically and economically important tree species are crucial to deciphering the influence of environmental factors and intraspecific variability on tree growth and performance under climate change to guide assisted gene flow and assisted migration of tree provenances and species. In this context, we compared inter-annual trends in tree-ring widths (carbon sequestration potential) and vessel characteristics (conductivity optimisation) of four beech provenances in two international provenance trials, one in Slovenia (Kamenski hrib, a core beech growing site) and one in Hungary (Bucsuta, a marginal beech site) in 2009–2019. We found different patterns of inter-annual variability in mean vessel area and tree-ring widths among provenances and sites, pointing to diverse genetic background and environmental influence on these two wood-anatomical traits. The average values of the vessel area varied less between provenances at Kamenski hrib than at Bucsuta. Weather conditions differently affected tree-ring width and mean vessel area. Furthermore, the length of the period of response of vessel area to the analysed weather conditions differed in summer and winter periods. The differences in the mean vessel area within the tree ring were more pronounced in the weather-wise extreme years, regardless of the provenance. Consistent with previous studies, we confirmed that site conditions affect the climate sensitivity of trees, which is more pronounced at marginal sites or in extreme years. The findings on how different environmental conditions affect the radial growth of young beech trees of different origin are very important for future forest management.

Cilostazol induces vasorelaxation through the activation of the eNOS/NO/cGMP pathway, prostanoids, AMPK, PKC, potassium channels, and calcium channels

ObjectiveThis study aimed to investigate vasoactive effect mechanisms of cilostazol in rat thoracic aorta. Materials and methodsThe vessel rings prepared from the thoracic aortas of the male rats were placed in the chambers of the isolated tissue bath system. The resting tone was adjusted to 1 g. Following the equilibration phase, potassium chloride or phenylephrine was used to contract the vessel rings. When achieving a steady contraction, cilostazol was applied cumulatively (10−8–10−4 M). In the presence of potassium channel blockers or signaling pathway inhibitors, the same experimental procedure was performed. ResultsCilostazol exhibited a significant vasorelaxant effect in a concentration-dependent manner (pD2: 5.94 ± 0.94) (p < .001). The vasorelaxant effect level of cilostazol was significantly reduced by the endothelial nitric oxide synthase inhibitor L-NAME (10−4 M), soluble guanylate cyclase inhibitor methylene blue (10 µM), cyclooxygenase 1/2 inhibitor indomethacin (5 µM), adenosine monophosphate-activated protein kinase inhibitor compound C (10 µM), non-selective potassium channel blocker tetraethylammonium chloride (10 mM), large-conductance calcium-activated potassium channel blocker iberiotoxin (20 nM), voltage-gated potassium channel blocker 4-Aminopyridine (1 mM), and inward-rectifier potassium channel blocker BaCl2 (30 µM) (p < .001). Moreover, incubation of cilostazol (10−4 M) significantly reduced caffeine (10 mM), cyclopiazonic acid (10 µM), and phorbol 12-myristate 13-acetate-induced (100 µM) vascular contractions (p < .001). ConclusionsIn the rat thoracic aorta, the vasodilator action level of cilostazol is quite noticeable. The vasorelaxant effects of cilostazol are mediated by the eNOS/NO/cGMP pathway, prostanoids, AMPK pathway, PKC, potassium channels, and calcium channels.

Radiation Damage Analysis of FNSF Components Using McCad and MCNP

The Fusion Energy System Studies Fusion Nuclear Science Facility (FESS-FNSF) concept represents a transitional step between ITER and a commercial fusion power plant. The FNSF is a conceptualized D-T fueled tokamak with 518 MW of fusion power that has been extensively used to explore and optimize design features. The energetic 14.1-MeV neutrons can produce significant localized heating and activations, and can cause damage to plasma-facing components, which can determine maintenance/outage scheduling needs and also impact the lifetime of the device as a whole. This study illustrates a neutronics analysis that was conducted on a 22.5-degree symmetric sector of the FNSF with the goal of understanding the neutron heating and radiation damage that can be characterized by quantifying the displacements per atom (dpa). Concurrently, this study also focused on the development of analysis capabilities by converting a three-dimensional computer-aided design model of the FNSF into MCNP6.2 input using the McCad code. Accordingly, some confirmatory results on tritium production and the tritium breeding ratio (TBR) are provided to support model validation. The results produced by MCNP6.2 simulations showed that the highest heating and damage occurred in the outboard region, which concentrated approximately 290 MW of the total nuclear heating, in contrast to 97 MW within the inboard region. These results are consistent with previous studies that employed earlier versions of the FNSF concept and different modeling approaches. This study also provides additional details on neutron wall loading, as well as total heating from neutrons and gammas, results which show the total heating of the device (16 sectors) is approximately 477.83 ± 0.80% MW, indicating a neutron energy multiplication factor of 1.15. Additionally, the capability to calculate hydrogen and helium production, as well as dpa, is illustrated. Finally, the neutronics effects of using alternative materials to tungsten carbide were evaluated for the vacuum vessel, low-temperature shield, and structural ring components, which showed that compounds like YH2, Mg(BH4)2, and ZrH2 could reduce the total heating on the magnet and also reduce the TBR.

Analysis of prognostic risk factors and development of a predictive model for fetuses with right aortic arch with mirror-image branching: a prognostic evaluation method based on ultrasound parameter features.

Prenatal ultrasound plays a crucial role in the diagnosis and classification of right aortic arch (AO) with mirror-image branching (RAA-MB). The recent research in this area has primarily focused on qualitative diagnosis, neglecting the quantitative analysis of ultrasound factors that impact RAA-MB outcomes. This study used echocardiography to measure prenatal ultrasound parameters for vascular ring and trachea in fetuses with RAA-MB, employing a nomogram model to evaluate factors influencing their prognosis, thereby providing a comprehensive characterization of potential outcomes. A retrospective case-control study was conducted from March 2019 to March 2023. A systematic gathering of prenatal echocardiograms and clinical data was completed for a cohort comprising 92 cases of fetal RAA-MB at the Ultrasound Medicine Center of Gansu Provincial Maternity and Child Care Hospital. Participant recruitment was executed through random selection from among those receiving outpatient medical care. Within the cohort, 42 cases were categorized as fetuses with isolated RAA-MB, while the remaining 50 cases were characterized as fetuses with RAA-MB and associated anomalies. Measurements were taken of the angle between the right AO and the ductus arteriosus (DA) (AO-DA), the distance between the AO and DA, the diameter of AO and DA, and the distance growth rate (DGR) of the AO-DA distance. Additionally, measurements were taken of the tracheal anterior-posterior diameter, tracheal left-right diameter, and tracheal circumference in the three-vessel tracheal view. In the AO view, measurements were taken of the tracheal cross-sectional area (TA) and the vessel ring cross-sectional area (VRA). The relationship between these parameters and the prognosis of fetuses with RAA-MB was assessed using logistic regression analysis. A receiver operating characteristic (ROC) curve was constructed to evaluate the diagnostic performance of the predictive model based on these factors. The multivariate logistic regression analysis revealed that the independent predictive factors for the prognosis of fetuses with RAA-MB were the AO-DA distance [odds ratio (OR) =0.012], TA (OR =0.401), and VRA (OR =1.103) (all P values <0.001). The area under the ROC curve was 0.891 [95% confidence interval (CI): 0.789-0.914; P<0.001], indicating a high accuracy of the model's predictions. The AO-DA distance, TA, and VRA are factors that influence the prognosis of fetuses with RAA-MB. The column chart model constructed based on these parameters can effectively provide a reference for predicting the risk of adverse outcomes in fetuses with RAA-MB.

Genetic variability of traits of the laticiferous system and association with rubber yield in juvenile and adult rubber tree progenies

The objectives of this study were to investigate genetic variation and association of the traits of the laticiferous system with rubber yield in young and adult rubber tree progenies Hevea brasiliensis, and compare the traits of the laticiferous system at different heights of the adult trees. The genetic material is composed of progenies from open pollination from the rubber tree breeding program of IAC, evaluated in the experimental field of UNESP in Ilha Solteira, SP, Brazil, in the young and adult phases, and in the Polo Regional Alta Mogiana of the Agência Paulista de Tecnologia do Agronegócio in Colina, SP, Brazil in the young phase. A randomized block experimental design was used with 30 treatments (progenies), three replications, and 10 plants per plot. The following traits were evaluated: rubber yield (RY), virgin bark thickness (BT), number of rings of laticiferous vessels (NR), and mean distance between consecutive rings of the laticiferous vessels (MD). The individual statistical analyses and repeated measurements were performed through mixed linear models using the REML/BLUP (Restricted Maximum Likelihood/Best Linear Unbiased Prediction) procedure. Genetic and phenotypic correlations were also estimated. The accuracy estimates (Aˆc) for the traits in the two locations were higher (> 0.7), indicating good perspectives in a breeding program. The coefficient of genetic variation (CVg %) showed low variation between the sites: BT (4.5–7 %), NR (14.1–18.3 %), and MD (15–18.2 %). The NR expressed higher heritabilities and was therefore the best trait of the laticiferous system for predicting genetic values; it showed expressive genetic correlations with RY, and may be used in indirect selection. BT did not show progeny × height interaction, indicating that the classification of the progenies was the same, regardless of the tree height at collection. To select progenies in common in the young and adult ages, using analysis of measurements repeated in time, the most suitable height for collection of samples in the adult progenies for the traits of the laticiferous system was up to 80 cm. The traits of the laticiferous system collected at 30 cm in young progenies are associated with RY, both in the youth phase and in the adult phase. They can be used to assist in early or indirect selection of rubber tree progenies.

Prolonged Exposure to Intestinal Edemagenic Stress Decreases Mesenteric Lymphatic Contractility

Mesenteric lymphatic vessels (MLVs) are the primary route for removal of excess intestinal interstitial fluid. Lymphatic pumping, the virtue of the intrinsic contractility of lymphatic muscle, is necessary for active lymph transport to the venous circulation and thus resolution of interstitial edema. Acute exposure to edemagenic stress has been reported to increase contractility and pumping of MLVs. However, our recent studies revealed that when exposure to edemagenic stress is prolonged, lymphatic contraction frequency decreases and pump failure ensues. It is unknown how the ability of lymphatic muscle to generate active tension is affected in these maladapted MLVs. Therefore, the purpose of the present study was to evaluate our hypothesis that prolonged exposure to edemagenic stress decreases lymphatic muscle contractility.Male Sprague Dawley rats underwent midline laparotomy with 3‐day exposure to either venous hypertension (VHT; induced by coarctation of superior mesenteric vein), fluid overload (HD; induced by daily IV infusion of 80 ml/kg lactated Ringer’s saline), or neither (SHAM; no additional intervention). In isometric biomechanics studies, MLVs were mounted on a wire myograph and perfused with warm APSS. Vessel rings were incrementally stretched, stimulated with substance P (1 µM) in 60 mM K+‐APSS (SP K‐APSS), followed by wash out with APSS. This sequence was repeated and the following steady state tensions were recorded at each level of stretch: unstimulated total tension (passive stretch, in APSS), stimulated total tension (SP K‐APSS), and passive tension (Ca++‐free APSS, at the end of the experiment). The circumferential length at the level of stretch yielding optimal delta tension (= stimulated total tension ‐ unstimulated total tension) for each vessel was identified as Lmax. Additionally, unstimulated active tension (= unstimulated total tension ‐ passive tension) and stimulated active tension (= stimulated total tension ‐ passive tension) were calculated.Vessels from VHT and SHAM groups yielded nearly identical length‐tension relationships. However, compared to SHAM and VHT vessels, HD vessels generated significantly lower tension across all indices: unstimulated total tension, stimulated total tension, passive tension, unstimulated active tension, and stimulated active tension. At optimal stretch (Lmax), the delta tension was lower in HD vessels than SHAM or VHT vessels.Consistent with findings of the previous studies, prolonged exposure to intestinal edemagenic stress induced mesenteric lymphatic pump failure in VHT and HD vessels. However, lymphatic muscle contractility was reduced only in HD vessels. Taken together, these findings suggest that peri‐ and post‐oprative fluid therapy in major surgery patients receiving fluid therapy may lead to mesenteric lymphatic maladaptation. The consequential decrease in intestinal lymph drainage would then contribute to delayed resolution of intestinal edema, increased morbidity and extended hospital stays.

Vascular Functional Effect Mechanisms of Elabela in Rat Thoracic Aorta

Elabela is a recently discovered peptide hormone. The present study aims to investigate the vasorelaxant effect mechanisms of elabela in the rat thoracic aorta. The vascular rings obtained from the thoracic aortas of the male Wistar albino rats were placed in the isolated tissue bath system. Resting tension was set to 1gram. After the equilibration period, the vessel rings were contracted with phenylephrine or potassium chloride. Once a stable contraction was achieved, elabela-32 was applied cumulatively (10-9-10-6molar) to the vascular rings. The experimental protocol was repeated in the presence of specific signaling pathway inhibitors or potassium channel blockers to determine the effect mechanisms of elabela. Elabela showed a significant vasorelaxant effect in a concentration-dependent manner (P<0.001). The vasorelaxant effect level of elabela was significantly reduced by the apelin receptor antagonist F13A, cyclooxygenase inhibitor indomethacin, adenosine monophosphate-activated protein kinase inhibitor dorsomorphin, protein kinase C inhibitor bisindolmaleimide, large-conductance calcium-activated potassium channel blocker iberiotoxin, and intermediate-conductance calcium-activated potassium channel blocker TRAM-34 (P<0.001). However, the vasorelaxant effect level of elabela was not significantly affected by the endothelial nitric oxide synthase inhibitor nitro-L-arginine methyl ester and mitogen-activated protein kinase inhibitor U0126. Elabela exhibits a prominent vasodilator effect in rat thoracic aorta. Apelin receptor, prostanoids, adenosine monophosphate-activated protein kinase, protein kinase C, and calcium-activated potassium channels are involved in the vasorelaxant effect mechanisms of elabela.

Morphological Variation of Circle of Willis in Nepali Population: A 3D Time-of-Flight Magnetic Resonance Angiography Based Study

Introduction: The Circle of Willis (COW) is an anatomic ring of vessels located at the base of the brain connecting the anterior and posterior circulation by uniting the internal carotid and vertebrobasilar systems to maintain adequate cerebral perfusion. The importance of detailed information of the COW morphology and integrity in any patient cannot be overemphasized, especially for neurophysicians, neurosurgeons, and interventional neuroradiologists who are considering intervention to the intracranial arteries. This study was conducted to study the variation of COW among the Nepalese population and compare the results with those of other nationalities. Methods: It was a prospective cross-sectional study performed using a 1.5 Tesla MRI machine. Complete anatomical assessment of the COW was done. The anterior and posterior components of COW were defined as per the standard literature and evaluated in detail. Results: A total of 118 patients were studied during the period out of which 75 (63.6%) were males and 43 (36.4%) were females. A morphologically normal COW configuration was found only in 55 (46.6%) cases whereas a variant configuration was present in 63 (53.4%) cases. The most common variation was noted in the posterior communicating artery (PCOM) which was present in 42 (67%) cases. The most common single variation in abnormal COW configuration was absent right PCOM. Conclusion: The morphologic variation of the COW is more common than the normal textbook configuration in the Nepalese population, PCOM being the most commonly involved vessel.

Involvement of 3',5'-cyclic inosine monophosphate in cystathionine γ-lyase-dependent regulation of the vascular tone.

Background and Purposel‐cysteine or hydrogen sulfide (H2S) donors induce a biphasic effect on precontracted isolated vessels. The contractile effect occurs within a concentration range of 10 nM to 3 μM followed by vasodilatation at 30–100 μM. Here, we have investigated the signalling involved in the H2S‐induced contraction.Experimental ApproachVascular response to NaHS or l‐cysteine is evaluated on isolated precontracted with phenylephrine vessel rings harvested from wild type, cystathionine γ‐lyase (CSE−/−), soluble guanylyl cyclase (sGCα1 −/−) and endothelial nitric oxide synthase (eNOS−/−) knock‐out mice. The cAMP, cGMP and inosine 3′,5′‐cyclic monophosphate (cIMP) levels are simultaneously quantified using ultra‐performance liquid chromatography–tandem mass spectrometry (UPLC‐MS/MS) analysis. The involvement of sGC, phosphodiesterase (PDE) 4A and PDE5 are also evaluated.Key ResultsCSE‐derived H2S‐induced contraction requires an intact eNOS/NO/sGC pathway and involves cIMP as a second messenger. H2S contractile effect involves a transient increase of cGMP and cAMP metabolism caused by PDE5 and PDE4A, thus unmasking cIMP contracting action. The stable cell‐permeable analogue of cIMP elicits concentration‐dependent contraction on a stable background tone induced by phenylephrine. The lack of cIMP, coupled to the hypocontractility displayed by vessels harvested from CSE−/− mice, confirms that H2S‐induced contraction involves cIMP.Conclusion and ImplicationsThe endothelium dynamically regulates vessel homeostasis by modulating contractile tone. This also involves CSE‐derived H2S that is mediated by cIMP.

The peculiarities of pulmonary macro- and microhemodynamics changes after treatment with agonists and blockers of cholinoceptors

Background. The pulmonary arterial and venous vessels are innervated by parasympathetic cholinergic nerves. However, the studies, performed on the isolated rings of pulmonary vessels, can not give answer to the question about the role of cholinergic mechanisms in the changes of pulmonary circulation in full measure.&#x0D; Aim. The comparative analysis of the changes of the pulmonary macro- and microhemodynamics after acetylcholine, atropine, pentamine and nitroglycerine treatment.&#x0D; Materials and methods. The study was carried out on the anesthetized rabbits in the condition of intact circulation with the measurement of the pulmonary artery pressure and flow, venae cavae flows, cardiac output, and also on isolated perfused lungs in situ with stabilized pulmonary flow with measurement of the perfused pulmonary artery pressure, capillary hydrostatic pressure, capillary filtration coefficient and calculation of the pulmonary vascular resistance, pre- and postcapillary resistances.&#x0D; Results. In the conditions of intact circulation after acetylcholine, pentamine and nitroglycerine treatment the pulmonary artery pressure and flow decreased, the pulmonary vascular resistance did not change as a result of decreasing of pulmonary artery flow and left atrial pressure due to diminution of venous return and venae cavaе flows. On perfused isolated lungs acetylcholine caused the increasing of pulmonary artery pressure, capillary hydrostatic pressure, pulmonary vascular resistance, pre- and postcapillary resistance and capillary filtration coefficient. After M-blocker atropine treatment the indicated above parameters of pulmonary microcirculation increased, on the contrary, after N-blocker pentamine treatment they decreased. Nitroglycerine infusion caused less decreasing of the parameters of pulmonary microcirculation in comparison with effects of pentamine, but capillary filtration coefficient decreased to a greater extent. These data indicate that nitroglycerine decreases endothelial permeability of pulmonary microvessels.&#x0D; Conclusion. After activation or blockade of cholinergic mechanisms in the condition of intact circulation the calculated parameter of pulmonary vascular resistance is depended from the ratio of the pulmonary artery pressure and flow and left atrial pressure, which are determined by the venous return. The different character of the changes of pulmonary microcirculatory parameters after M-blocker atropine and N-blocker pentamine treatment is evidence of reciprocal relations of M- and N-cholinoceptors in the nervous regulation of the pulmonary microcirculatory bed.

Multi-century tree-ring anatomical evidence reveals increasing frequency and magnitude of spring discharge and floods in eastern boreal Canada

Abstract In eastern boreal Canada, variability in river discharge is poorly understood at the multi-century scale due to short instrumental records. In recent decades, increased magnitude and frequency of spring floods have raised concerns about the potential effects of climate change on flood risk. Unlike tree-ring width, flood rings have a demonstrated dendrochronological utility for reconstructing high discharge in boreal environments. In this study, twelve chronologies of earlywood vessel cross-sectional area (a new hydrological proxy) and ring width were developed from riparian Fraxinus nigra trees periodically flooded in spring. These chronologies were used as predictors of Harricana River spring discharge, which was reconstructed for the period 1771–2016. The reconstruction captured 69% of the variance over a 102-year calibration period. The reconstruction indicates that the magnitude and frequency of spring high discharge has increased since the end of the Little Ice Age (1850–1870 CE) and since 1950. The change from a multi-decadal frequency in the late 19th century to a decadal and then interannual frequency in the late 20th century is associated with an increase in snow cover over much of central-eastern Canada. The association between the reconstructed spring discharge and spring atmospheric circulation indices NINO3.4, AMO, NAO may also have changed in these periods and further work is needed to assess the stability of these associations. The correlation between reconstructed and instrumental spring discharge at the regional scale, as well as the shared features in reconstructed discharge and other paleorecords from subarctic Quebec suggest a common hydrological signal across the study area and for the early 20th to 21st centuries. The unprecedently low and high spring discharge in recent decades compared to the historical natural variability of the last 250 years also suggests that the increase in flood frequency and magnitude originates from climate change.

Vasoactive effect of a sheet sample of Oxytenanthera abyssinica (Poaceae) on a model of coronary arteries of pigs

Background: The cost of treatments for cardiovascular diseases, in particular for populations in developing countries such as Senegal, requires an alternative which consists in developing research into new therapeutic approaches with the use of plants from the traditional pharmacopoeia. On the other hand, many of these plants have not been the subject of scientific studies. Aims and Objectives: In our study, we set out to study the effects on the vasomotricity of a plant from an in vitro model. As specific objectives, research of the vasorelaxant effects of the hydroethanolic extract of the leaves of Oxytenanthera abyssinica, on a model of pig coronary artery. Materials and Methods: The coronary artery rings were incubated with O. abyssinica (FOA) leaf extract at different concentrations (10–4 mg/ml, 5.10–4 mg/ml, 10–3 mg/ml, 5.10–3 mg/ml, 10–2 mg/ml, 5.10–2 mg/ml, 10–1 mg/ml, and 5.10–1 mg/ml) in an isolated organ system. The device comprises a set of devices including isometric tension sensors. The vessel rings to be studied are mounted on these. They are connected to metal rods that develop isometric tension. These sensors make it possible to measure the intensity of the voltage developed which reflects the vascular reactivity. After incubation, the rings are contracted with U46619 to produce a concentration-contraction curve with and without endothelium. The measured voltages are collected and represented in the form of a curve using the GraphPad software Prism version 6.01®. The results are expressed as means ± SEM of 08 experiments. The analysis of variance test (ANOVA) was used to compare the means. P < 0.05 was considered statistically significant. Results: The results obtained in this study showed that on isolated pig coronary artery rings, contracted at U46619, the hydroethanolic extract of O. abyssinica (FOA) leaves induces vascular relaxation. This vasorelaxation is obtained at concentrations ranging from 10−4 to 5.10−1 mg/ml with a relaxation percentage of approximately 100%. This percentage of relaxation is obtained both in the presence and in the absence of functional endothelium. These results suggest that the hydroethanolic extract of leaves of O. abyssinica possesses dose-dependent vasodilator properties on isolated pig coronary artery rings with endothelium-independent character. It thus appears that the raw extract of leaves of O. abyssinica can act on two ways. Conclusion: The results of our study made it possible to demonstrate a vascular relaxing effect of the hydroethanolic extract of the leaves of O. abyssinica. This vasorelaxant effect is dose dependent and endothelium independent.

Relationships between yield and some anatomical and morphological traits in rubber tree progenies

The present work evaluated the relationship of rubber yield with morphological and structural traits of the laticiferous system in rubber tree [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell. Arg] open-pollinated progenies to understand the cause and effect relationships between traits in order to enable future early selection. The progenies were installed in Jaú, Pindorama and Votuporanga in a randomized block design, with five replications and 10 plants per plot at a spacing of 2.0 × 2.0 m. The traits evaluated at three years of age were rubber yield (Yld); girth (Grt), expressed by the stem perimeter; bark thickness (BT); number of latex vessel rings (RG); length (PL), diameter (PD) and petiole index (PI); leaflet length(LFL) and width (LFW); leaf width (LW), area (LA) and index (LI); and number of leaf storeys (NLS). Coefficients of the genotypic correlations were used for a graphical representation of the correlation network created in the Genes program. Subsequently, the diagnosis of multicollinearity, as well as the analysis of the direct and indirect genotypic correlations of bark anatomical traits, leaf morphological traits, girth, and rubber yield, were performed. The traits that showed significant genotypic correlations with rubber yield at the three evaluated sites were girth, bark thickness, and number of leaf storeys. The girth character had the largest direct effect on rubber yield. Canonical correlation analysis showed that selection for the number of leaf storeys may increase at least three of the traits (yield, girth, bark thickness, and number of latex vessel rings) for most locations studied. There is an association between the yield traits (yield, girth, and the laticiferous system) and the morphological traits.

Xylem anatomy of Robinia pseudoacacia L. and Quercus robur L. is differently affected by climate in a temperate alluvial forest

Xylem hydraulic traits of native Quercus robur are more sensitive to previous-summer drought than those of alien Robinia pseudoacacia. The latter modulates vessel traits and ring porosity to cope with inter-annual climate variability, and is less affected by extreme events. This suggests that R. pseudoacacia might be more competitive under future drier conditions. Forest management strategies require knowledge on how co-occurring native and alien species respond to unprecedented climate conditions, which can severely affect xylem conductivity and tree performance. We aimed at quantitatively comparing xylem anatomical traits of co-occurring native Quercus robur and alien Robinia pseudoacacia and assessing similarities and differences in their response to climate variability. We analyzed tree-ring anatomy and built chronologies of several parameters related to vessel number, size, and theoretical conductivity. Mean chronologies for each parameter were correlated to monthly temperature and precipitation data for the period 1954–2005 and within 30-year moving windows. We also assessed responses to extreme conditions in 2003. Quercus robur showed typical ring-porous vessel distribution, while R. pseudoacacia modulated vessel size and number year by year, frequently showing semi-ring porous appearance. Previous rainy summers increased size of large vessels in Q. robur, and number of large vessels in R. pseudoacacia. In winter, R. pseudoacacia was sensitive to water excess. High temperature in March increased vessel size in Q. robur, but reduced it in R. pseudoacacia. The 2003 summer heatwave strongly reduced vessel size and number in the following year in Q. robur, but had much less effect on R. pseudoacacia. Quercus robur xylem traits are more influenced by both inter-annual climate variability and extreme events than those of R. pseudoacacia. Lower performance under dry conditions might reduce competitiveness of Q. robur in the future, slowing down the natural replacement of the invasive pioneer R. pseudoacacia by later-stage Q. robur.

Aerobic exercise-induced inhibition of PKCα/CaV1.2 pathway enhances the vasodilation of mesenteric arteries in hypertension

Regular exercise is regarded as a nonpharmacological therapy for controlling hypertension by improving the function of vascular smooth muscle cells (VSMCs). The underlying mechanism is unclear. L-type-voltage-dependent Ca2+ channel (CaV1.2) on the plasma membrane and PKCα of VSMCs are pivotal modulators of vascular tone. PKCα is hyperactivated and concentrated at the surface membrane during hypertension. This study investigated the effects of aerobic exercise on the PKCα and CaV1.2 in mesenteric arterial smooth muscle cells from spontaneously hypertensive rats (SHRs). SHRs and Wistar-Kyoto (WKY) rats were randomly assigned into sedentary groups (SHR-SED and WKY-SED) and exercise training groups (SHR-EX and WKY-EX). Exercise groups were performed a 12-week moderate-intensity (18–20 m/min) treadmill training. Mesenteric arterial mechanical and functional properties were evaluated. Exercise reduced body weight and systolic blood pressure in both SHR-EX and WKY-EX. PDBu (PKC activator) and BayK 8644 (CaV1.2 agonist) elicited vasoconstriction, while Gö6976 (PKCα inhibitor) and nifedipine (CaV1.2 blocker) induced vasodilation of the vessel rings. In SHRs, exercise normalized the increased vascular sensitivity to these activators and inhibitors. Nifedipine greatly suppressed PDBu-induced vasoconstriction. Upon incubation with Gö6976, the effects of both PDBu and nifedipine were markedly suppressed. In patch-clamp studies, PDBu increased and Gö6976 decreased the CaV1.2 current density. Exercise ameliorated the responses of both PDBu and Gö6976 in SHRs. Immunofluorescence staining suggested that exercise training alleviated the hypertension-induced increase of colocalization rate of PKCα and CaV1.2 α1C subunit in VSMCs. These data indicate that hypertension enhanced PKCα/CaV1.2 pathway-induced constriction of mesenteric arteries, and this pathological enhancement is inhibited by aerobic exercise training.

Stereotactic radiofrequency ablation of primary liver tumors in the caudate lobe

BackgroundThe encasement of the caudate lobe by a vascular ring of large vessels may apart from the technical difficulties in needle placement increase the probability of local recurrence after thermal ablation due to cooling effects. This single-center retrospective study evaluates the results after multiprobe stereotactic radiofrequency ablation (SRFA) of hepatocellular carcinoma (HCC) in the caudate lobe. MethodsTwenty patients underwent 24 multiple-probe SRFA sessions for the treatment of 24 HCCs in the caudate lobe. Eight of twenty patients had initially solitary tumors, the remaining 12 patients suffered from multifocal disease. ResultsThe median tumor size was 1.5 cm (range: 1–8 cm). After a mean follow-up of 21 months one local recurrence in the caudate lobe was observed resulting in a local recurrence rate of 4.2% (1/24). The overall survival rates at 1, 3, and 5 years from the date of the first SRFA were 95%, 59%, and 44%, respectively, with a median overall survival of 51.3 months. The disease-free survival after SRFA was 48%, 24% and 24%, at 1, 3 and 5 years, respectively. One patient suffering from Child C liver cirrhosis died due to septic shock 26 days after SRFA and one postinterventional complication required minimal invasive interventional treatment. ConclusionMultiprobe SRFA for HCC in the caudate lobe appears to be safe and feasible. The overall outcome is at least comparable to that of surgical resection, with low perioperative mortality and only minimal morbidity.

Neonates from women with pregestational maternal obesity show reduced umbilical vein endothelial response to insulin

ObjectivePregestational maternal obesity (PGMO) associates with foetoplacental vascular endothelial dysfunction and higher risk for insulin resistance in the neonate. We characterised the PGMO consequences on the insulin response of the human foetoplacental vasculature. MethodsUmbilical veins were from pregnancies where the mother was with PGMO (body mass index 30–42.3 kg/m2, n = 33) or normal pregestational weight (PGMN) (body mass index 19.5–24.4 kg/m2, n = 21) with total gestational weight gain within the physiological range. Umbilical vein ring segments were mounted in a myograph for isometric force measurements. Primary cultures of human umbilical vein endothelial cells were used in passage 3. Vessel rings and cells were exposed to 1 nmol/L insulin (20 min) in the absence or presence of 100 μmol/L NG-nitro-l-arginine methyl ester (inhibitor of nitric oxide synthase, NOS). ResultsVessel rings from PGMO showed reduced nitric oxide synthase-activity dependent dilation to insulin or calcitonin-gene related peptide compared with PGMN. PGMO associated with higher inhibitor phosphorylation of the insulin receptor substrate 1 (IRS-1) and lower activator phosphorylation of protein kinase B/Akt (Akt). Cells from PGMO also showed lower nitric oxide level and reduced activator serine1177 but increased inhibitor threonine495 phosphorylation of endothelial nitric oxide synthase (eNOS) and saturable transport of l-arginine. HUVECs from PGMO were not responsive to insulin. ConclusionThe lack of response to insulin by the foetoplacental endothelium may result from reduced IRS-1/Akt/eNOS signalling in PGMO. These findings may result in higher risk of insulin resistance in neonates to PGMO pregnancies.

Arterial “inflammaging” drives vascular calcification in children on dialysis

Children on dialysis have a cardiovascular mortality risk equivalent to older adults in the general population, and rapidly develop medial vascular calcification, an age-associated pathology. We hypothesized that premature vascular ageing contributes to calcification in children with advanced chronic kidney disease (CKD). Vessels from children with Stage 5 CKD with and without dialysis had evidence of increased oxidative DNA damage. The senescence markers p16 and p21 were also increased in vessels from children on dialysis. Treatment of vessel rings ex vivo with calcifying media increased oxidative DNA damage in vessels from children with Stage 5 CKD, but not in those from healthy controls. Vascular smooth muscle cells cultured from children on dialysis exhibited persistent DNA damage, impaired DNA damage repair, and accelerated senescence. Under calcifying conditions vascular smooth muscle cells from children on dialysis showed increased osteogenic differentiation and calcification. These changes correlated with activation of the senescence-associated secretory phenotype (SASP), an inflammatory phenotype characterized by the secretion of proinflammatory cytokines and growth factors. Blockade of ataxia-telangiectasia mutated (ATM)-mediated DNA damage signaling reduced both inflammation and calcification. Clinically, children on dialysis had elevated circulating levels of osteogenic SASP factors that correlated with increased vascular stiffness and coronary artery calcification. These data imply that dysregulated mineral metabolism drives vascular “inflammaging” by promoting oxidative DNA damage, premature senescence, and activation of a pro-inflammatory SASP. Drugs that target DNA damage signaling or eliminate senescent cells may have the potential to prevent vascular calcification in patients with advanced CKD.

Sulfasalazine reduces placental secretion of antiangiogenic factors, up-regulates the secretion of placental growth factor and rescues endothelial dysfunction.

BackgroundPreeclampsia is a major complication of pregnancy with no medical treatment. It is associated with placental oxidative stress, hypoxia and inflammation leading to soluble fms-like tyrosine kinase 1 (sFlt-1) and soluble endoglin (sENG) secretion and reduced placental growth factor (PlGF). This results in widespread endothelial dysfunction causing hypertension and multisystem organ injury. Sulfasalazine is an anti-inflammatory and antioxidant medication used to treat autoimmune disease. Importantly, it is safe in pregnancy. We examined the potential of sulfasalazine to quench antiangiogenic factors and endothelial dysfunction and increase angiogenic factor secretion.MethodsWe performed functional experiments using primary human pregnancy tissues to examine the effects of sulfasalazine on sFlt-1, sENG and PlGF secretion. Sulfasalazine is known to inhibit nuclear factor kappa-light-chain-enhancer of activated B cells (NFkB) and upregulate heme-oxygenase 1 (HO-1) thus we explored the effect of these transcription factors on sFlt-1 secretion from human cytotrophoblasts. We examined the ability of sulfasalazine to reduce key markers of endothelial dysfunction and dilate whole blood vessels.FindingsWe demonstrate sulfasalazine administration reduces sFlt-1 and sENG and upregulates PlGF secretion from human placental tissues. Furthermore sulfasalazine mitigates endothelial dysfunction in several in vitro/ex vivo assays. It enhanced endothelial cell migration and proliferation, promoted blood vessel dilation (vessels obtained from women at caesarean section) and angiogenic sprouting from whole blood vessel rings. The effect of sulfasalazine on the secretion of sFlt-1 was not mediated through either the NFkB or HO-1 pathways.InterpretationWe conclude that sulfasalazine reduces sFlt-1 and sENG secretion and endothelial dysfunction and upregulates PlGF. Sulfasalazine has potential to treat or prevent preeclampsia and warrants investigation in clinical trials.FundingThis work was funded by The National Health and Medical Research Council of Australia (NHMRC; #1048707, #1046484. #1101871, #1064845), an Arthur Wilson RANZCOG scholarship and a Norman Beischer Medical Research Foundation grant. FB was supported by a NHMRC Early Career Fellowship (NHMRC #1142636). NJH was supported by a CR Roper Research Fellowship. The NHMRC provided salary support (#1136418 to ST #1062418 to TKL, #1064845 to SS). The funders had no role in study design, data collection, analysis, decision to publish or the preparation of the manuscript.

New macular findings in individuals with biallelic KLHL7 gene mutation

ObjectiveThe ubiquitin-proteasome system pathway has been recognised as a crucial cellular mechanism for the proper function of photoreceptor cells. In particular, ubiquitin ligases (E3s) recognise and ubiquitinate specific proteins for...