Efflux Rate Research Articles

Quantitative Predictors of Response to Neoadjuvant Chemotherapy on Dynamic Contrast-enhanced 3T Breast MRI.

To assess whether changes in quantitative parameters on breast MRI better predict pathologic complete response (pCR) to neoadjuvant chemotherapy (NAC) in breast cancer than change in volume. This IRB-approved retrospective study included women with newly diagnosed breast cancer who underwent 3T MRI before and during NAC from January 2013 to December 2019 and underwent surgery at our institution. Clinical data such as age, histologic diagnosis and grade, biomarker status, clinical stage, maximum index cancer dimension and volume, and surgical pathology (presence or absence of in-breast pCR) were collected. Quantitative parameters were calculated using software. Correlations between clinical features and MRI quantitative measures in pCR and non-pCR groups were assessed using univariate and multivariate logistic regression. A total of 182 women with a mean age of 52 years (range, 26-79 years) and 187 cancers were included. Approximately 45% (85/182) of women had pCR at surgery. Stepwise multivariate regression analysis showed statistical significance for changes in quantitative parameters (increase in time to peak and decreases in peak enhancement, wash out, and Kep [efflux rate constant]) for predicting pCR. These variables in combination predicted pCR with 81.2% accuracy and an area under the curve (AUC) of 0.878. The AUCs of change in index cancer volume and maximum dimension were 0.767 and 0.613, respectively. Absolute changes in quantitative MRI parameters between pre-NAC MRI and intra-NAC MRI could help predict pCR with excellent accuracy, which was greater than changes in index cancer volume and maximum dimension.

Rationale for different formulations of omega-3 fatty acids leading to differences in residual cardiovascular risk reduction

Rationale for different formulations of omega-3 fatty acids leading to differences in residual cardiovascular risk reduction

Bicalutamide may enhance kidney injury in diabetes by concomitantly damaging energy production from OXPHOS and glycolysis

Bicalutamide (Bic), frequently used in androgen-deprivation therapy for treating prostate cancer, was demonstrated to induce multiple apoptosis and fibrosis pathways and mitochondrial dysfunction in renal mesangial cells. Whether Bic also damages the glycolytic pathway has never been cited. To investigate this, we performed an in vitro model study with mesangial cells, and at the same time, collected data from an in vivo experiment. Bic induced hypoxia-inducible factor (HIF)-1 which upregulates phosphorylated-5′-AMP-activated protein kinase (p-AMPK) and severely suppresses the rate of adenosine triphosphate (ATP) production in both the oxidative phosphorylation and glycolysis pathways. Bic suppressed the oxygen consumption rate, extracellular acidification rate, and mitochondrial proton efflux rate, downregulated in vivo but upregulated in vitro glucose transporter (GLUT)-1, reduced glucose uptake, inhibited key glycolytic enzymes, including phosphofructokinase (PFK), pyruvate kinase (PK), and pyruvate dehydrogenase (PDH), and upregulated hexokinase II (HKII) and lactic dehydrogenase A (LDHA). In vivo, Bic downregulated renal cubilin levels, thereby disrupting the glomerular reabsorption function. Conclusively, Bic can damage bioenergenesis from both mitochondria and glycolysis. It was suggested that long-term administration of Bic can initiate renal damage depending on the duration and dose of treatment, which requires cautious follow-up.

Changing lanes: seasonal differences in cellular metabolism of adipocytes in grizzly bears (Ursus arctos horribilis).

Obesity is among the most prevalent of health conditions in humans leading to a multitude of metabolic pathologies such as type 2 diabetes and hyperglycemia. However, there are many wild animals that have large seasonal cycles of fat accumulation and loss that do not result in the health consequences observed in obese humans. One example is the grizzly bear (Ursus arctos horribilis) that can have body fat content > 40% that is then used as the energy source for hibernation. Previous in vitro studies found that hibernation season adipocytes exhibit insulin resistance and increased lipolysis. Yet, other aspects of cellular metabolism were not addressed, leaving this in vitro model incomplete. Thus, the current studies were performed to determine if the cellular energetic phenotype-measured via metabolic flux-of hibernating bears was retained in cultured adipocytes and to what extent that was due to serum or intrinsic cellular factors. Extracellular acidification rate and oxygen consumption rate were used to calculate proton efflux rate and total ATP defined as both ATP from glycolysis and from mitochondrial respiration. Hibernation adipocytes treated with hibernation serum produced less ATP and exhibited lower maximal respiration and glycolysis ratesthan active season adipocytes. These effects were reversed with serum from the opposite season. Insulin had little influence on total ATP production and lipolysis in both hibernation and active serum-treated adipocytes. Together, these results suggest that the metabolic suppression occurring in hibernation adipocytes are downstream of insulin signaling and likely due to a combined reduction in mitochondria number and/or function and glycolytic processes. Future elucidation of the serum components and the cellular mechanisms that enable alterations in mitochondrial function could provide a novel avenue for the development of treatments for human metabolic diseases.

Discovery of New Terms Associated with the Navier-Stokes Momentum Balance Equation and Finding the Evidence of Its Inapplicability to Govern Fluid Flow in the Infinite Space

Our modeling fluid flow, especially if the fluid is referred to as a gas, is established on mimicking each particle/molecule’s movement and then gathering that movement into macro quantities characterizing the fluid flow. It has resulted in discovering a new principle of the property (mass, momentum, and energy) balance in space. We named it the Ballistic Principle of the Property Balance in Space as described earlier in our publications. This paper uses a different scheme of defining a net rate of total property efflux than our original paper. Using this scheme, we formulated integro-differential forms of mass balance and momentum balance equations adapted to the incompressible fluid flow (gas flow with a mass-flow velocity less than 0.3 Ma) at the non-uniform temperature in the infinite gas space. We also investigated the analytical behavior of the integro-differential equations in the region bounding the point of singularity by applying the Taylor series expansion method to transform the integro-differential mass and momentum balance equations into the corresponding vector differential equations. Then we compared them with the Navier-Stokes equations of mass and momentum conservation for an incompressible fluid. We were surprised to find that the Navier-Stokes momentum balance equation does not describe the fluid flow adequately. Particularly, it does not consider the momentum associated with the part of velocity acquired by each gas particle during its free path traveling in the body force field. Also, the Navier-Stokes momentum balance equation is silent about the influence of the temperature non-uniformity on the momentum balance. Finally, we have demonstrated that the Navier-Stokes equations are not applicable to govern fluid flow on R3 × [0, ∞).

Mitochondrion-targeted supramolecular "nano-boat" simultaneously inhibiting dual energy metabolism for tumor selective and synergistic chemo-radiotherapy.

Rationale: Tumor energy metabolism has been a well-appreciated target of cancer therapy; however, the metabolism change of cancer cells between oxidative phosphorylation and glycolysis poses a challenge to the above. In this study, we constructed an innovative mitochondrion-targeted supramolecular “nano-boat” based on peptide self-assembly for tumor combined chemo-radiotherapy by simultaneously inhibiting the dual energy metabolism.Methods: A lipophilic self-assembled peptide and a positively charged cyclen were integrated to fabricate a brand new mitochondrion-targeted nano-platform for the first time. The indices of mitochondrial dysfunction including mitochondrial membrane potential, apoptosis proteins expression and ultrastructure change were evaluated using a JC-1 probe, western blotting and biological transmission electron microscopy, respectively. Energy metabolism assays were conducted on a Seahorse XF24 system by detecting the oxygen consumption rate and the glycolytic proton efflux rate. The radio-sensitization effect was investigated by colony formation, the comet assay, and γ-H2AX staining.Results: The supramolecular “nano-boat” could selectively kill cancer cells by much higher enrichment and reactive oxygen species generation than those in normal cells. In the cancer cells treated with the supramolecular “nano-boat”, the dysfunctional morphological changes of the mitochondrial ultrastructure including swelling and pyknosis were evidently observed, and the endogenous mitochondrial apoptosis pathway was effectively triggered by abundant of cytochrome C leaking out. Concurrently, the dual metabolic pathways of glycolysis and oxidative phosphorylation were severely inhibited. More importantly, the supramolecular “nano-boat” displayed an excellent radio-sensitization effect with a sensitization enhancement ratio value as high as 2.58, and hence, in vivo efficiently combining radiotherapy yielded an enhanced chemo-radiotherapy effect.Conclusion: Our study demonstrated that the rationally designed peptide-based “nano-boat” could efficiently induce cancer cell apoptosis by the energy metabolism inhibition involving multiple pathways, which may provide the motivation for designing novel and universal mitochondria-targeted drug delivery systems for cancer therapy.

TCA-phospholipid-glycolysis targeted triple therapy effectively suppresses ATP production and tumor growth in glioblastoma.

Rationale: Glioblastoma (GBM) displays a complex metabolic reprogramming in cancer cells. Adenosine triphosphate (ATP) is one of the central mediators of cell metabolism and signaling. GBM cells generate ATP by glycolysis and the tricarboxylic acid (TCA) cycle associated with oxidative phosphorylation (OXPHOS) through the breaking-down of pyruvate or fatty acids to meet the growing energy demand of cancer cells. Therefore, it's urgent to develop novel treatments targeting energy metabolism to hinder tumor cell proliferation in GBM.Methods: Non-targeted metabolomic profiling analysis was utilized to evaluate cell metabolic reprogramming using a small molecule inhibitor (SMI) EPIC-0412 treatment. Cellular oxygen consumption rate (OCR) and the total proton efflux rate (PER), as well as ATP concentration, were tracked to study metabolic responses to specifically targeted inhibitors, including EPIC-0412, arachidonyl trifluoromethyl ketone (AACOCF3), and 2 deoxy-D-glucose (2-DG). Cancer cell proliferation was assessed by CCK-8 measurements and colony formation assay. Additionally, flow cytometry, immunoblotting (IB), and immunofluorescence (IF) analyses were performed with GBM cells to understand their tumorigenic properties under treatments. Finally, the anticancer effects of this combination therapy were evaluated in the GBM mouse model by convection-enhanced delivery (CED).Results: We found that SMI EPIC-0412 could effectively perturb the TCA cycle, which participated in the combination therapy of cytosolic phospholipase A2 (cPLA2)-inhibitor AACOCF3, and hexokinase II (HK2)-inhibitor 2-DG to disrupt the GBM energy metabolism for targeted metabolic treatments. ATP production was significantly declined in glioma cells when treated with monotherapy (EPIC-0412 or AACOCF3), dual therapy (EPIC-0412 + AACOCF3), or triple therapy (EPIC-0412 + AACOCF3 +2-DG) regimen. Our experiments revealed that these therapies hindered glioma cell proliferation and growth, leading to the reduction in ATP production and G0/G1 cell cycle arrest. We demonstrated that the combination therapy effectively extended the survival of cerebral tumor-bearing mice.Conclusion: Our findings indicate that the TCA-phospholipid-glycolysis metabolism axis can be blocked by specific inhibitors that significantly disrupt the tumor energy metabolism and suppress tumor proliferation in vitro and in vivo, suggesting that targeting ATP synthesis inhibition in cancer cells might be an attractive therapeutic avenue in GBM management.

Carbon potentials of different biochars derived from municipal solid waste in a saline soil

There are numerous studies conducted on biochar for its carbon (C) sequestration potential; however, there are limited studies available on the behavior of salt-affected soils related to biochar application. Therefore, more studies are needed to elucidate the mechanisms through which biochar affects saline soil properties. In this study, biochars were produced from solid waste at pyrolysis temperatures of 300, 500, and 700 °C (BC300, BC500, and BC700, respectively) and applied to a saline soil to evaluate their impacts on soil carbon dioxide (CO 2 ) efflux, C sequestration, and soil quality. A soil incubation experiment lasting for 107 d was conducted. The results showed that soil CO 2 efflux rate, cumulative CO 2 emission, active organic C (AOC), and organic matter (OM) significantly increased with BC300 application to a greater extent than those with BC500 and BC700 as compared to those in the no-biochar control (CK). However, soil C non-lability did not significantly increase in the treatments with biochars, except BC700, as compared to that in CK. Besides improving the soil quality by increasing the soil AOC and OM, BC300 showed positive impacts in terms of increasing CO 2 emission from the saline soil, while BC500 and BC700 showed greater potentials of sequestering C in the saline soil by increasing the soil non-labile C fraction. The recalcitrance index ( R 50 ) values of BC500 and BC700 were > 0.8, indicating their high stability in the saline soil. It could be concluded that biochars pyrolyzed at high temperatures (≥ 500 °C) could be suitable in terms of C sequestration, while biochars pyrolyzed at low temperatures (≤ 300 °C) could be suitable for improving saline soil quality.

A Ratiometric Calcium Reporter CGf Reveals Calcium Dynamics Both in the Single Cell and Whole Plant Levels Under Heat Stress.

Land plants evolved to quickly sense and adapt to temperature changes, such as hot days and cold nights. Given that calcium (Ca2+) signaling networks are implicated in most abiotic stress responses, heat-triggered changes in cytosolic Ca2+ were investigated in Arabidopsis leaves and pollen. Plants were engineered with a reporter called CGf, a ratiometric, genetically encoded Ca2+ reporter with an mCherry reference domain fused to an intensiometric Ca2+ reporter GCaMP6f. Relative changes in [Ca2+]cyt were estimated based on CGf’s apparent KD around 220 nM. The ratiometric output provided an opportunity to compare Ca2+ dynamics between different tissues, cell types, or subcellular locations. In leaves, CGf detected heat-triggered cytosolic Ca2+ signals, comprised of three different signatures showing similarly rapid rates of Ca2+ influx followed by differing rates of efflux (50% durations ranging from 5 to 19 min). These heat-triggered Ca2+ signals were approximately 1.5-fold greater in magnitude than blue light-triggered signals in the same leaves. In contrast, growing pollen tubes showed two different heat-triggered responses. Exposure to heat caused tip-focused steady growth [Ca2+]cyt oscillations to shift to a pattern characteristic of a growth arrest (22%), or an almost undetectable [Ca2+]cyt (78%). Together, these contrasting examples of heat-triggered Ca2+ responses in leaves and pollen highlight the diversity of Ca2+ signals in plants, inviting speculations about their differing kinetic features and biological functions.

Intracellular Water Lifetime as a Tumor Biomarker to Monitor Doxorubicin Treatment via FFC-Relaxometry in a Breast Cancer Model.

This study aims to explore whether the water exchange rate constants in tumor cells can act as a hallmark of pathology status and a reporter of therapeutic outcomes. It has been shown, using 4T1 cell cultures and murine allografts, that an early assessment of the therapeutic effect of doxorubicin can be detected through changes in the cellular water efflux rate constant kio. The latter has been estimated by analyzing the magnetization recovery curve in standard NMR T1 measurements when there is a marked difference in the proton relaxation rate constants (R1) between the intra- and the extra-cellular compartments. In cellular studies, T1 measurements were carried out on a relaxometer working at 0.5 T, and the required difference in R1 between the two compartments was achieved via the addition of a paramagnetic agent into the extracellular compartment. For in-vivo experiments, the large difference in the R1 values of the two-compartments was achieved when the T1 measurements were carried out at low magnetic field strengths. This task was accomplished using a Fast Field Cycling (FFC) relaxometer that was properly modified to host a mouse in its probe head. The decrease in kio upon the administration of doxorubicin is the result of the decreased activity of Na+/K+-ATPase, as shown in an independent test on the cellular uptake of Rb ions. The results reported herein suggest that kio can be considered a non-invasive, early and predictive biomarker for the identification of responsive patients immediately from the first doxorubicin treatment.

The role of plant functional traits and diversity in soil carbon dynamics within riparian agroforests.

Restoration of agricultural riparian buffers with trees (agroforestry) provides an elegant solution to enhance carbon storage while also augmenting local biodiversity. Yet the scope and role of riparian plant community diversity in key soil dynamics remain unresolved. Operationalizing riparian age (young [<10 yr] and mature [>30 yr] since establishment] and forest stand type (coniferous and deciduous dominant) to capture the potential extent of plant diversity, we measured plant functional trait diversity and community weighted mean trait values, microbial composition, abiotic soil conditions, and rates of soil CO2 efflux (mg CO2 -C m-2 h-1 ). We used piecewise structural equation modeling (SEM) to further refine the role of biotic indices (leaf, root, and microbial characteristics), and abiotic factors (soil physio-chemical metrics) on soil C cycling processes in riparian systems. We found significantly lower rates of CO2 efflux (F=8.47; p<.01) over one growing season and higher total soil C (F=3.46; p=.03) in mature buffers compared with young buffers. Using SEM, we describe influences on soil C content (marginal r2 =61) and soil CO2 efflux (marginal r2 =53). Within young buffers, soil C content was significantly predicted by fungal/bacterial ratio and root length density, whereas in mature buffers, tree leaf characteristics were associated with soil C content. Soil CO2 efflux was predicted by soil moisture, soil carbon content, and herbaceous root characteristics. Evidently, leaf and root functional traits in combination with broad soil parameters significantly describe soil C dynamics in the field; however, significant pathways are not the same throughout the life cycle of a riparian agroforest.

Improving resveratrol bioavailability using water-in-oil-in-water (W/O/W) emulsion: Physicochemical stability, in vitro digestion resistivity and transport properties

• Novel W/O/W multiple emulsion for delivering of resveratrol was built. • W/O/W multiple emulsion showed excellent stability under different pH, temperature and long-time storaging. • W/O/W multiple emulsion reflected a good resistance to peristalsis and digestive juices until the intestine. • The transport of resveratrol in W/O/W multiple emulsion across Caco-2 monolayer cell was passive diffusion. • W/O/W multiple emulsion shown potential ability to improve the bioavailability of resveratrol. Evaluations have been made about the physicochemical stability in water-in-oil-in-water (W/O/W) emulsion loaded with resveratrol under different pH, NaCl concentration, temperature, and storage time. The in vitro digestion and Caco-2 cell transport were also investigated. Results showed W/O/W emulsion remained stable at pH 2–8, temperatures of 25–70 °C and could be stable storage for 77 days. With an increase in NaCl concentration from 1 to 500 mM, the zeta potential changed from −40 mV to −10 mV, but the droplets size didn’t show any significant change. The in vitro digestion showed W/O/W emulsion could maintain the structure until small intestine which could give higher protecting for resveratrol. Meanwhile, W/O/W emulsion could reduce the efflux rate of resveratrol across the Caco-2 cell monolayers and special complex of W/O/W emulsion could delay resveratrol release. Results indicated that W/O/W emulsion was suitable vehicle for resveratrol and could improve its bioavailability considering those complicated influence factors.

Study on the intestinal permeability of lamivudine using Caco-2 cells monolayer and Single-pass intestinal perfusion

BackgroundThe aim of this work is to investigate the intestinal permeability of lamivudine and explore its absorption mechanism. MethodCaco-2 cells monolayer and single-pass intestinal perfusion (SPIP) were selected for the investigation of lamivudine under different conditions, such as different concentration, absorption time, bidirectional transportation, and transportation with efflux transporters inhibitor. The concentration of lamivudine both in Caco-2 cells monolayer samples and SPIP samples was detected by HPLC-UV. Then the permeability parameters were calculated. ResultsThe established HPLC-UV method reach the requirements for detection. There is no statistically difference between absorption parameters of lamivudine both in Caco-2 cells monolayer and SPIP (P > 0.05) under different dose groups. After transportation with efflux transporters inhibitor, the efflux rate of lamivudine in three dose groups was significantly decreased from 2.67, 2.59 and 2.59 to 1.78, 1.61, and 1.81 respectively. Lamivudine exhibits an absorption mechanism of passive diffusion. ConclusionThe absorption of lamivudine may be related to efflux transporters. In addition, lamivudine is a moderate-permeability drug in Biopharmaceutics Classification System.

Physiologically-based pharmacokinetic modeling to evaluate in vitro-to-in vivo extrapolation for intestinal P-glycoprotein inhibition.

As one of the key components in model‐informed drug discovery and development, physiologically‐based pharmacokinetic (PBPK) modeling linked with in vitro‐to‐in vivo extrapolation (IVIVE) is widely applied to quantitatively predict drug–drug interactions (DDIs) on drug‐metabolizing enzymes and transporters. This study aimed to investigate an IVIVE for intestinal P‐glycoprotein (Pgp, ABCB1)‐mediated DDIs among three Pgp substrates, digoxin, dabigatran etexilate, and quinidine, and two Pgp inhibitors, itraconazole and verapamil, via PBPK modeling. For Pgp substrates, assuming unbound Michaelis‐Menten constant (K m) to be intrinsic, in vitro‐to‐in vivo scaling factors for maximal Pgp‐mediated efflux rate (J max) were optimized based on the clinically observed results without co‐administration of Pgp inhibitors. For Pgp inhibitors, PBPK models utilized the reported in vitro values of Pgp inhibition constants (K i), 1.0 μM for itraconazole and 2.0 μM for verapamil. Overall, the PBPK modeling sufficiently described Pgp‐mediated DDIs between these substrates and inhibitors with the prediction errors of less than or equal to ±25% in most cases, suggesting a reasonable IVIVE for Pgp kinetics in the clinical DDI results. The modeling results also suggest that Pgp kinetic parameters of both the substrates (K m and J max) and the inhibitors (K i) are sensitive to Pgp‐mediated DDIs, thus being key for successful DDI prediction. It would also be critical to incorporate appropriate unbound inhibitor concentrations at the site of action into PBPK models. The present results support a quantitative prediction of Pgp‐mediated DDIs using in vitro parameters, which will significantly increase the value of in vitro studies to design and run clinical DDI studies safely and effectively.

Mining Institute, Far Eastern Branch of the Russian Academy of Sciences

The problem of processing sands from polymineral placer deposits of the Far Eastern region is a complex technical and technological process. The predominance of high-clay placers with high content of valuable components of small and thin fractions is noted. At the same time the content of fine gold fractions smaller than 0.5 mm reach more than 90 % at some sites with the predominance of fractions smaller than 0.3 mm. The necessity to improve the technologies and technical facilities for processing placer high-clay sands with a high content of fine and nanoscale particles of valuable components is substantiated. Therefore, the purpose of the study is to substantiate approaches to the construction of a phenomenological model for processing of placer high-clay sands by gravitational methods to ensure safety of crystals and reduce the loss of valuable components with reduced energy intensity. On the basis of the proposed exponential dependence of variation of specific interfacial surface of mineral particles on system thermodynamic potential, it has been found out that interdependence of hydraulic fluid efflux and flow rates plays a decisive role in microdesintegration of mineral particles under conditions of turbulization initiated by the jet falling on the flat surface of the cavitation reactor. The calculations performed allowed to estimate the growth of the specific interfacial surface of particles in the intervals of 1.8–3.3 times depending on regulation of hydraulic fluid flow rate, its density and initiation time. Presented mathematical dependencies will allow to control the process when testing cavitation reactor, assess installation quality and operation nature, as well as adjust the design and introduce necessary changes. We propose a general processing scheme for placers with the use of a number of innovative installations of a new type including those based on the combination of turbulence and cavitation at low energy intensity. The impact of hydrodynamic effects initiated by turbulent effects and cavitation on hydraulic fluid of high-clay sands is able to ensure reliable microdesintegration-dispersion and provide a significant reduction in technological losses of valuable components. The study results obtained can be used for further development of theoretical approaches to the description of cavitation processes modeled in proposed installations.

Benthic nutrient fluxes in deep-sea sediments within the Laurentian Channel MPA (eastern Canada): The relative roles of macrofauna, environment, and sea pen octocorals

In order to characterize spatial patterns and environmental and biological drivers of organic matter remineralization and nutrient regeneration in deep-sea sedimentary habitats, we measured fluxes of nitrate, nitrite, ammonium, phosphate, and silicate at the sediment-water interface during 48-h ex situ incubation of sediment cores. We sampled a total of 6 stations (351–445 m depth) inside the Laurentian Channel Marine Protected Area (MPA), on the outer continental shelf of Newfoundland (Canada). We assessed the potential effect of octocoral sea pens on uni- and multivariate benthic nutrient fluxes at large- and small-scale by comparing sea pen fields and other sedimentary habitats, and cores with and without sea pens. For each station, we evaluated a wide range of environmental variables, including physico-chemical and sedimentary factors, and we identified macrofaunal organisms inhabiting the cores, assessed their taxonomic diversity, community composition, and biological trait expression. Our analysis identified macrofaunal species richness and the density of a few key taxa, as well as environmental factors such as the quantity of sedimentary organic matter as the primary drivers of variation of multivariate benthic fluxes. Macrofauna explained up to 41% of the variation in benthic fluxes, whereas environmental variables only explained up to 19%, highlighting the importance of biodiversity for ecosystem functioning. Uni- and multivariate analysis of fluxes did not reveal clear spatial patterns within the MPA habitats and stations, and fluxes showed high small-scale variability. We found enhanced ammonium efflux rates associated with the presence of sea pens at both small- and large-scale, likely reflecting both direct and indirect effects of these soft corals on organic matter deposition and sedimentary biogeochemical processes. Sea pens, however, did not appear to influence other fluxes, leaving their role for organic matter remineralization unclear. The extreme complexity and small-scale heterogeneity of benthic processes, particularly within what appears to be a relatively homogeneous environment, underscores the need for further studies to facilitate generalizations of patterns and drivers of benthic nutrient fluxes at larger scales, which will ultimately enable the effective integration of ecosystem functioning into conservation strategies.

Arbuscular mycorrhizal symbioses alleviating salt stress in maize is associated with a decline in root-to-leaf gradient of Na+/K+ ratio

BackgroundInoculation of arbuscular mycorrhizal (AM) fungi has the potential to alleviate salt stress in host plants through the mitigation of ionic imbalance. However, inoculation effects vary, and the underlying mechanisms remain unclear. Two maize genotypes (JD52, salt-tolerant with large root system, and FSY1, salt-sensitive with small root system) inoculated with or without AM fungus Funneliformis mosseae were grown in pots containing soil amended with 0 or 100 mM NaCl (incrementally added 32 days after sowing, DAS) in a greenhouse. Plants were assessed 59 DAS for plant growth, tissue Na+ and K+ contents, the expression of plant transporter genes responsible for Na+ and/or K+ uptake, translocation or compartmentation, and chloroplast ultrastructure alterations.ResultsUnder 100 mM NaCl, AM plants of both genotypes grew better with denser root systems than non-AM plants. Relative to non-AM plants, the accumulation of Na+ and K+ was decreased in AM plant shoots but increased in AM roots with a decrease in the shoot: root Na+ ratio particularly in FSY1, accompanied by differential regulation of ion transporter genes (i.e., ZmSOS1, ZmHKT1, and ZmNHX). This induced a relatively higher Na+ efflux (recirculating) rate than K+ in AM shoots while the converse outcoming (higher Na+ influx rate than K+) in AM roots. The higher K+: Na+ ratio in AM shoots contributed to the maintenance of structural and functional integrity of chloroplasts in mesophyll cells.ConclusionAM symbiosis improved maize salt tolerance by accelerating Na+ shoot-to-root translocation rate and mediating Na+/K+ distribution between shoots and roots.

Ultrasound-targeted simvastatin-loaded microbubble destruction promotes OA cartilage repair by modulating the cholesterol efflux pathway mediated by PPARγ in rabbits.

AimsTo evaluate the effect of ultrasound-targeted simvastatin-loaded microbubble destruction (UTMDSV) for alleviation of the progression of osteoarthritis (OA) in rabbits through modulation of the peroxisome proliferator-activated receptor (PPARγ).MethodsIn vitro, OA chondrocytes were treated with ultrasound (US), US-targeted microbubble destruction (UTMD), simvastatin (SV), and UTMDSV on alternate days for four weeks. Chondrocytes were also treated with PPARγ inhibitor, PPARγ inhibitor+ UTMDSV, and UTMDSV. The cholesterol efflux rate and triglyceride levels were measured using an assay kit and oil red O staining, respectively. In vivo, the OA rabbits were treated with a single intra-articular injection of UTMD, SV, and UTMDSV every seven days for four weeks. Cartilage histopathology was assessed by safranin-O staining and the Mankin score. Total cholesterol (TC) and high-density lipoprotein-cholesterol (HDL-C) in rabbit knee synovial fluid were detected by enzyme-marker assay. Aggrecan, collagen II, and PPARγ expression levels were analyzed by Western blotting (WB).ResultsIn vitro, UTMDSV significantly increased the cholesterol efflux rate and aggrecan, collagen II, and PPARγ levels in OA chondrocytes; these effects were blocked by the PPARγ inhibitor. In vivo, UTMDSV significantly increased aggrecan, collagen II, PPARγ, and HDL-C levels, while TC levels and Mankin scores were decreased compared with the UTMD, SV, OA, and control groups.ConclusionUTMDSV promotes cartilage extracellular matrix synthesis by modulating the PPARγ-mediated cholesterol efflux pathway in OA rabbits.Cite this article: Bone Joint Res 2021;10(10):693–703.

Multiparametric Magnetic Resonance Imaging, 68Ga Prostate-Specific Membrane Antigen Positron Emission Tomography-Computed Tomography, and Respective Quantitative Parameters in Detection and Localization of Clinically Significant Prostate Cancer in Intermediate- and High-Risk Group Patients: An Indian Demographic Study.

Objectives:The objective of this study was to evaluate the diagnostic accuracy of multiparametric magnetic resonance imaging (mpMRI) and 68Ga prostate-specific membrane antigen positron emission tomography–computed tomography (PSMA PET-CT) and respective quantitative parameters (Ktrans – influx rate contrast, Kep – efflux rate constant, ADC – apparent diffusion coefficient, and SUVmax ratio – prostate SUVmax to background SUVmax ratio) in detection and localization of clinically significant prostate cancer (CSPCa) in D’Amico intermediate- and high-risk group patients (prostate-specific antigen [PSA] >10 ng/ml).Methodology:The study included thirty-three consecutive adult men with serum prostate specific antigen >10ng/ml, and systematic 12 core prostate biopsy proven prostate cancer. All the 33 patients, were evaluated with mpMRI, and 68Ga PSMA PET-CT. The biopsy specimens and imaging were evaluated for 12 sectors per prostate by a predetermined scheme.Results:MpMRI Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) score ≥3 showed higher sensitivity than 68Ga PSMA PET-CT (96.3% vs. 82.4%), with similar specificity (54.5% vs. 54.5%) (n = 33 patients, 396 sectors). Combined use of MRI and 68Ga PSMA PET-CT in parallel increased sensitivity (99.5%) and NPV (98.7%) for detection of CSPCa and combined use of MRI and 68Ga PSMA PET-CT in series increased specificity (71.8%) and PPV (71.5%) (n = 33 patients, 396 sectors). ADC showed a strong negative correlation with Gleason score (r = −0.77), and the highest discriminative ability for detection and localization of CSPCa (area under curve [AUC]: 0.91), followed by Ktrans (r = 0.74; AUC: 0.89), PI-RADS (0.73; 0.86), SUVmax ratio (0.49; 0.74), and Kep (0.24; 0.66).Conclusion:MpMRI PI-RADS v2 score and 68Ga PSMA PET-CT (individually as well as in combination) are reliable tool for detection and localization of CSPCa. Quantitative MRI and 68Ga PSMA PET-CT parameters have potential to predict Gleason score and detect CSPCa.

DCE-MRI of Brain Fluid Barriers: In Vivo Water Cycling at the Human Choroid Plexus

ABSTRACT Metabolic deficits at brain–fluid barriers are an increasingly recognized feature of cognitive decline in older adults. At the blood–cerebrospinal fluid barrier, water is transported across the choroid plexus (CP) epithelium against large osmotic gradients via processes tightly coupled to activity of the sodium/potassium pump. Here, we quantify CP homeostatic water exchange using dynamic contrast-enhanced MRI and investigate the association of the water efflux rate constant (kco) with cognitive dysfunction in older individuals. Temporal changes in the longitudinal relaxation rate constant (R1) after contrast agent bolus injection were measured in a CP region of interest in 11 participants with mild cognitive dysfunction [CI; 73 ± 6 years] and 28 healthy controls [CN; 72 ± 7 years]. kco was determined from a modified two-site pharmacokinetic exchange analysis of the R1 time-course. Ktrans, a measure of contrast agent extravasation to the interstitial space was also determined. Cognitive function was assessed by neuropsychological test performance. kco averages 5.8 ± 2.7 s−1 in CN individuals and is reduced by 2.4 s−1 [ca. 40%] in CI subjects. Significant associations of kco with global cognition and multiple cognitive domains are observed. Ktrans averages 0.13 ± 0.07 min−1 and declines with age [–0.006 ± 0.002 min−1 yr−1], but shows no difference between CI and CN individuals or association with cognitive performance. Our findings suggest that the CP water efflux rate constant is associated with cognitive dysfunction and shows an age-related decline in later life, consistent with the metabolic disturbances that characterize brain aging.