Facilitated transport of ferrihydrite with phosphate under saturated flow conditions.

With increasing phosphate (P) entering the environment during agricultural application, the subsurface flow of particular P has been recently discussed as a vital P transport pathway. Iron (oxyhydr)oxide colloid-facilitated P transport is critical for iron and P biogeochemical processes in the subsurface. This study investigated the ferrihydrite colloid-facilitated P transport through adsorption and column experiments under different P concentrations and three pH conditions. Increased P loading on ferrihydrite colloids decreased the transport of ferrihydrite colloids (< 8.0%) under acid conditions through pore straining and irreversible attachment. Under neutral and alkaline conditions, ferrihydrite colloids exhibited more negative surfaces and smaller diameters with increasing P, which further enhanced ferrihydrite colloid transport (maximum to 95.6%). Ferrihydrite colloid-facilitated P transport was limited under acid conditions, and it was 10% - 57% enhancement under neutral and alkaline conditions with increasing P adsorption. Under neutral conditions, ferrihydrite colloid-facilitated P transport was strongest (maximum to 68.84%) because of its stronger ferrihydrite colloid transport than under acid conditions and larger P adsorption capacity than under alkaline conditions. Our findings indicate that the facilitated transport of ferrihydrite colloids in the presence of P may be appreciable in iron and phosphate-rich soil and subsurface systems, which is essential for evaluating the fate of iron and iron-facilitated P and potential environmental risks of P transport in the subsurface.

Effects of carbonate on ferrihydrite transformation in alkaline media.

Alkaline media widely exist in natural and engineered systems such as semiarid/arid areas, radioactive waste sites, and mine tailings. In these settings, the commonly occurring iron (oxyhydr)oxides differed in their ability to influence the fate of nutrients and contaminants. Due to the substantially increased atmospheric carbon dioxide (CO2) concentration, carbonate stands to increase in these media. However, how increasing carbonate affects the transformation of poorly crystalline iron (oxyhydr)oxides (e.g., two-line ferrihydrite) under alkaline conditions still remains unclear. Here, kinetics of ferrihydrite transformation were evaluated at pH ∼10 as a function of [carbonate] = 0-286 mM using synchrotron-based X-ray and vibrational spectroscopic techniques. The results showed that carbonate slowed down ferrihydrite transformation slightly and suppressed goethite formation, but promoted hematite formation regardless of its concentration. At low carbonate concentration (11.42 mM), the effect of carbonate on product formation was obvious due to the weak inner-sphere complex; however, at high carbonate concentration (80-286 mM), the effect was retarded because of the adsorption equilibrium of carbonate as well as the initial carbonate adsorption followed by desorption. Moreover, carbonate modified the morphology of hematite from rhombic to ellipsoidal to honeycomb and goethite from rod-like to needle-like to spindle-like due to the inner-sphere adsorption-desorption of carbonate and adsorption of hydroxyl ions on reactive sites of iron (oxyhydr)oxides in alkaline media. The results suggest that the concurrently increasing carbonate with enhanced atmospheric CO2 could control the transformation and occurrence of iron (oxyhydr)oxides in natural and engineered environments and have important implications for the biogeochemical cycles of iron and carbon.

Posteromedial Portal Technique With Bone-Patellar Tendon-Bone Graft for Inside-Out Revision of Anterior Cruciate Ligament Reconstruction.

Bone-patellar tendon-bone (BTB) is a graft material used in anterior cruciate ligament (ACL) reconstruction. We describe creating a femoral tunnel using an inside-out posteromedial (PM) portal technique during anatomic double-bundle ACL reconstruction with a hamstring graft. We hypothesized that applying this femoral tunnel creation method to the revision ACL reconstruction using BTB would enable reconstruction in 1 stage. In this technique, an anteromedial, an anterolateral, and a PM portal are created to confirm the original ACL footprint and location and direction of the bone tunnel during primary reconstruction. The surgeon then drills from the PM portal, so that the femoral tunnel opening touches the posterior proximal articular cartilage margin in the ACL footprint. Even if the opening partially overlaps with the primary tunnel, it is possible to create a new tunnel with a different direction. Finally, the BTB graft is guided from the tibial tunnel to the femoral tunnel and fixed with interference screws. Intraoperative PM arthroscopic views can confirm that the femoral tunnel has been created, avoiding overlap, and that the revision ACL has been reconstructed. This procedure may be useful for 1-stage revision ACL reconstruction for reinjury after primary ACL reconstruction by other conventional procedures.

The clinical results of bi-cruciate vs posterior stabilized total knee arthroplasty for flexion contracture in osteoarthritic knee.

BACKGROUND: The improvement of flexion contracture is important in knee arthroplasty since residual flexion contracture postoperatively is associated with decreased quality of life and patient satisfaction. In this study, we investigated the effect of bi-cruciate stabilized (BCS)-type total knee arthroplasty (TKA) as compared to posterior stabilized (PS)-type TKA on osteoarthritic primary knees with flexion contractures. METHODS: 59 TKAs from January 2014 to December 2020, of which 30 were PS-type TKAs (NexGen LPS-flexⓇ; 76.3 years, BMI 27.5) and 29 BCS-type TKAs (Journey IIⓇ; 72.5 years, BMI 28.6), were performed for knee osteoarthritis with preoperative flexion contracture of 15° or greater. Full extension was obtained intraoperatively during all TKAs. Clinical outcomes, radiological evaluations, and the amount of additional distal femoral osteotomy during TKA were evaluated in a retrospective study design. RESULTS: The range of motion improved in the both groups. Postoperative flexion contracture was significantly improved in the BCS group. Knee Society Score improved significantly in both groups, with no difference between the two groups. The amount of additional distal femoral osteotomy was 2.5 ± 1.3 mm for the PS group, and 1.8 ± 1.5 mm for the BCS group, showing a significant difference (p = 0.04). DISCUSSION: The BCS-type TKA significantly improved preoperative flexion contracture and reduced the amount of additional distal femoral osteotomy compared to PS-type TKA. This is attributed to the anterior cam in the BCS-type TKA, which leads to a smaller amount of protrusion of the posterior femoral condyle from the posterior margin of the tibial component in the BCS-type in knee extension, as compared to the PS-type.

Spectroscopic Investigation of Phosphorus Mineralization as Affected by the Calcite-Water Interfacial Chemistry.

The mineralization and bioavailability of phytic acid, the predominant organic phosphorus (OP) species in many soils, have generally been rendered limited due to its interaction with soil minerals. In particularly calcareous and neutral to slightly alkaline soils, phytic acid is known to actively react with calcite, although how this interaction affects phytic acid mineralization is still unknown. This study, therefore, investigated the mechanisms regarding how the calcite-water interface influences phytic acid mineralization by phytase, at pHs 6 and 8 using in situ spectroscopic techniques including solution nuclear magnetic resonance and attenuated total reflection Fourier transform infrared spectroscopy. The findings indicated a pH-specific effect of the calcite-water interface. Inhibited phytase activity and thus impaired phytic acid mineralization were induced by calcite at pH 6, while the opposite effect was observed at pH 8. How the interaction between phytic acid and calcite and between phytase and calcite differed between the two pH values contributed to the pH-specific effect. The results demonstrate the importance of soil pH, enzyme-, and OP-clay mineral interactions in controlling the mineralization and transformation of OP and, consequently, the release of phosphate in soils. The findings can also provide implications for the management of calcite-rich and limed soils.

Four-year treatment continuation rates of osteoporosis drugs with different dosing intervals throughout Japan.

INTRODUCTION: There are approximately 13 million patients with osteoporosis in Japan; however, only 20% of them receive treatment. This study compared the 4-year continuation rates of osteoporosis drugs at different dosing intervals across throughout Japan. MATERIALS AND METHODS: Receipt data were analyzed to determine the continuation of osteoporosis medication in patients who began treatment at 210 hospitals throughout Japan between October 2016 and September 2017. Continuation rates were compared using Kaplan-Meier curves and log-rank tests. RESULTS: The 4-year continuation rates of daily, weekly, monthly, semi-annual, and yearly medications nationwide were 8.6%, 16.5%, 13.5%, 31.0%, and 26.0%, respectively. The 4-year continuation rates for semi-annual and yearly drugs were significantly higher than daily, weekly, monthly drugs. CONCLUSION: Throughout Japan, the 4-year treatment continuation rates of daily, weekly, monthly, semi-annual, and yearly osteoporosis drugs all decreased over time. However, the continuation rates of semi-annual and yearly drugs in the fourth year were significantly higher than those for the other dosing regimens. Therefore, injectable drugs with dosing intervals ≥6 months may improve continuation rates of osteoporosis drugs. Geriatr Gerontol Int 2023; 23: 665-670.

Hypoxia with or without Treadmill Exercises Affects Slow-Twitch Muscle Atrophy and Joint Destruction in a Rat Model of Rheumatoid Arthritis.

The effects of treadmill running under hypoxic conditions on joints and muscles of collagen-induced arthritis (CIA) rats were investigated. CIA rats were divided into normoxia no-exercise, hypoxia no-exercise (Hypo-no), and hypoxia exercise (Hypo-ex) groups. Changes were examined on days 2 and 44 of hypoxia with or without treadmill exercises. In the early stage of hypoxia, the expression of hypoxia-inducible factor (HIF)-1α increased in the Hypo-no and Hypo-ex groups. The expression of the egl-9 family hypoxia-inducible factor 1 (EGLN1) and vascular endothelial growth factor (VEGF) in the Hypo-ex group also increased. Under sustained hypoxia, the Hypo-no and Hypo-ex groups did not show increased expression of HIF-1α or VEGF, but p70S6K levels were elevated. Histologically, joint destruction was alleviated in the Hypo-no group, the loss of muscle weight in slow-twitch muscles was prevented, and muscle fibrosis was suppressed. In the Hypo-ex group, the preventive effect of a reduction in the slow-twitch muscle cross-sectional area was enhanced. Thus, chronic hypoxia in an animal model of rheumatoid arthritis controlled arthritis and joint destruction and prevented slow-twitch muscle atrophy and fibrosis. The combination of hypoxia with treadmill running further enhanced the preventive effects on slow-twitch muscle atrophy.

Enhanced and suppressed phosphorus mineralization by Ca complexation: NMR and CD spectroscopy investigation.

With the increasing demand for P fertilizer for world food production, the use of soil organic P fraction via mineralization could become an important P resource in agricultural soils. However, the predominant organic P species, phytic acid, has been considered rather recalcitrant to mineralization due to its active interaction with dissolved metals like Ca2+ in soil pore water. Calcium ions can be an inhibitor to many phytases, yet the mechanism was not clear. The objective of this study was to understand the effects of Ca2+(aq) on the phytase activity and inhibitory mechanisms using batch degradation kinetic experiments, Nuclear Magnetic Resonance (NMR) spectroscopy, Saturation Transfer Difference (STD) NMR, and Circular dichroism (CD) spectroscopy. The phytase activity followed Michaelis-Menten kinetics and increased Michaelis constant Km and decreased Vmax with Ca2+ addition were observed at pH 6. Therefore, mixed inhibition was the inhibition mechanism which was likely a result of the allosteric effect of Ca2+. The near-UV CD spectra supported phytase secondary conformational change upon the interaction between Ca2+ and the enzyme. It was found that phytase initially reacted with the D/L-3 phosphate of phytic acid at pH 6. At pH 8, the overall phytase activity decreased, yet the effect of Ca2+ on phytase activity was the opposite of that of pH 6. Enhanced phytase activity with Ca2+ addition was attributed to the structural change of phytic acid upon the Ca2+ complexation, which was confirmed by NOE spectra. The Ca2+-phytic acid complex might be a more favorable substrate than the free phytic acid. Unlike the findings from pH 6, Ca2+ didn't induce significant changes in either the near- or far-UV region of the CD spectra at pH 8. Furthermore, P5 was found to be the target of phytase at pH 8. The study revealed the pH-specific effects of Ca2+ on the mineralization of phytic acid.

Fe(II)-Catalyzed Transformation of Ferrihydrite with Different Degrees of Crystallinity.

Natural occurring ferrihydrite (Fh) nanoparticles have varying degrees of crystallinity, but how Fh crystallinity affects its transformation behavior remains elusive. Here, we investigated the Fe(II)-catalyzed transformation of Fh with different degrees of crystallinity (i.e., Fh-2h, Fh-12h, and Fh-85C). X-ray diffraction patterns of Fh-2h, Fh-12h, and Fh-85C exhibited two, five, and six diffraction peaks, respectively, indicating the order of crystallinity: Fh-2h < Fh-12h < Fh-85C. Fh with the lower crystallinity has a higher redox potential, corresponding to the faster Fe(II)-Fh interfacial electron transfer and Fe(III)labile production. With the increase of initial Fe(II) concentration ([Fe(II)aq]int.) from 0.2 to 5.0 mM, the transformation pathways of Fh-2h and Fh-12h change from Fh → lepidocrocite (Lp) → goethite (Gt) to Fh → Gt, but that of Fh-85C switches from Fh → Gt to Fh → magnetite (Mt). The changes are rationalized using a computational model that quantitatively describes the relationship between the free energies of formation for starting Fh and nucleation barriers of competing product phases. Gt particles from the Fh-2h transformation exhibit a broader width distribution than those from Fh-12h and Fh-85C. Uncommon hexagonal Mt nanoplates are formed from the Fh-85C transformation at [Fe(II)aq]int.= 5.0 mM. The findings are crucial to comprehensively understand the environmental behavior of Fh and other associated elements.

Cartilage degeneration of patellofemoral joint occurs in open wedge high tibial osteotomy, rather than in hybrid closed wedge high tibial osteotomy, during the early postoperative period: A qualitative analysis using MRI T2 mapping.

PURPOSE: After high tibial osteotomy, the patella may change position and osteoarthritis of the patellofemoral joint (PFJ) may occur. It was hypothesized that the course of PFJ degeneration would differ between open wedge high tibial osteotomy (OWHTO) and hybrid closed wedge high tibial osteotomy (hybrid HTO). Accordingly, this study aimed to evaluate the qualitative changes in PFJ articular cartilage, during the early postoperative period after OWHTO and hybrid HTO. METHODS: This was a retrospective observational study of 75 knees that underwent OWHTO (N = 37) or hybrid HTO (N = 38) for medial knee osteoarthritis. OWHTO and hybrid HTO were indicated for corrections of less than 10° and more than 10°, respectively. MRI of all knees was performed before and 6 months after surgery to evaluate patellar cartilage in sagittal images for T2 mapping. Three regions of interest (medial, middle, and lateral facets) were defined in the articular cartilage, and T2 values were measured. Patellar tilting angle, lateral shift ratio, and patellar height were compared before and after surgery. RESULTS: There was no significant change in arthroscopic findings of PFJ articular cartilage between the OWHTO and hybrid HTO groups. In the OWHTO group, the mean T2 value of medial and middle facets increased significantly (lateral, 43.0 ± 3.9 to 43.7 ± 3.5; middle, 44.2 ± 3.9 to 46.2 ± 3.8; medial 41.0 ± 4.3 to 42.4 ± 4.0). Conversely, no significant change was observed in the hybrid HTO group (lateral, 41.1 ± 4.0 to 42.3 ± 4.0; middle, 43.6 ± 4.2 to 44.5 ± 4.3; medial, 40.7 ± 4.1 to 41.5 ± 4.5). Patellar height decreased and increased in the OWHTO and hybrid HTO groups, respectively, and patellar tilt decreased in the OWHTO group. Lateral shift ratio decreased significantly in both groups. CONCLUSIONS: OWHTO with a small correction angle may result in qualitative changes in PFJ articular cartilage from an early stage, while hybrid HTO with a relatively large correction angle is unlikely to affect PFJ articular cartilage.

Analysis of the relationship between the morphology of the proximal tibiofibular joint and lateral hinge fracture in open wedge high tibial osteotomy.

BACKGROUND: One of the complications of open wedge high tibial osteotomy is lateral hinge fracture, which causes delayed bone healing. In this study, we focused on the morphology of the proximal tibiofibular joint to clarify the influence of this morphology on the occurrence of lateral hinge fracture in open wedge high tibial osteotomy. METHODS: The proximal tibiofibular joint of 58 knees in 55 patients who underwent open wedge high tibial osteotomy was classified as either horizontal or oblique, depending on the morphology of the fibular head. Lateral hinge fracture of Takeuchi classification type II or III was defined as unstable lateral hinge fracture. We analyzed whether patient background and bone morphological factors, including the morphology of the proximal tibiofibular joint, were associated with the occurrence of unstable lateral hinge fracture. RESULTS: The horizontal and oblique types were found in 34 and 24 knees, respectively. There was no difference in the percentage of hinge points within the safe zone between the horizontal and oblique types; however, there was a significant difference in the unstable lateral hinge fracture incidence between the two groups. Unstable lateral hinge fracture occurred in seven knees, mostly in patients with an oblique proximal tibiofibular joint. The factors associated with the occurrence of unstable lateral hinge fracture were analyzed using logistic regression analysis; the fibular head of the oblique type was a significant factor. CONCLUSION: Open wedge high tibial osteotomy for oblique-type proximal tibiofibular joints may be more likely to cause unstable lateral hinge fracture than the horizontal type.

Solution NMR investigation of phytic acid adsorption mechanisms at the calcite-water interface.

As one of the most abundant organic phosphorus (P) species in soils, phytic acid could serve as a mineralizable P reservoir in soils and sediments. It has been widely acknowledged that the adsorption of phytic acid to soil minerals retards P mineralization in soils. However, the adsorption mechanisms of phytic acid in the minerals are not clearly understood. Using solution 31P NMR and 1H-31P 2D NMR, the adsorption mechanism of phytic acid was investigated at the calcite-water interface at pH 6 and 8. Maximum phytic acid adsorption reached 3.07 mmol/g, 2.60 mmol/g, 2.39 mmol/g at pH 6, 8, and 9.5, respectively. The presence of outer-sphere surface complex was evident by a lack of significant change in zeta-potential of phytic acid reacted calcite. Solution NMR analysis showed a fast exchange process between adsorbed and unreacted phytic acid at the mineral surface on an NMR time scale, also indicating the outer-sphere complexation mechanism at both pH values. Interestingly, a more active role of P5 and P4,6 in binding with calcite surface was observed at pH 6. Adsorbed phytic acid on the calcite surface should be labile and is not limiting P mineralization in the terrestrial environment.

Endothelial Natriuretic Peptide Receptor 1 Play Crucial Role for Acute and Chronic Blood Pressure Regulation by Atrial Natriuretic Peptide.

BACKGROUND: ANP (atrial natriuretic peptide), acting through NPR1 (natriuretic peptide receptor 1), provokes hypotension. Such hypotension is thought to be due to ANP inducing vasodilation via NPR1 in the vasculature; however, the underlying mechanism remains unclear. Here, we investigated the mechanisms of acute and chronic blood pressure regulation by ANP. METHODS AND RESULTS: Immunohistochemical analysis of rat tissues revealed that NPR1 was abundantly expressed in endothelial cells and smooth muscle cells of small arteries and arterioles. Intravenous infusion of ANP significantly lowered systolic blood pressure in wild-type mice. ANP also significantly lowered systolic blood pressure in smooth muscle cell-specific Npr1-knockout mice but not in endothelial cell-specific Npr1-knockout mice. Moreover, ANP significantly lowered systolic blood pressure in Nos3-knockout mice. In human umbilical vein endothelial cells, treatment with ANP did not influence nitric oxide production or intracellular Ca2+ concentration, but it did hyperpolarize the cells. ANP-induced hyperpolarization of human umbilical vein endothelial cells was inhibited by several potassium channel blockers and was also abolished under knockdown of RGS2 (regulator of G-protein signaling 2), an GTPase activating protein in G-protein α-subunit. ANP increased Rgs2 mRNA expression in human umbilical vein endothelial cells but failed to lower systolic blood pressure in Rgs2-knockout mice. Endothelial cell-specific Npr1-overexpressing mice exhibited lower blood pressure than did wild-type mice independent of RGS2, and showed dilation of arterial vessels on synchrotron radiation microangiography. CONCLUSIONS: Together, these results indicate that vascular endothelial NPR1 plays a crucial role in ANP-mediated blood pressure regulation, presumably by a mechanism that is RGS2-dependent in the acute phase and RGS2-independent in the chronic phase.

Analysis of Hemodynamic Changes After Medial Patellofemoral Ligament Reconstruction.

The resumption of blood flow is an important factor in the remodeling process of the graft. The purpose of this study is to evaluate hemodynamic changes after medial patellofemoral ligament (MPFL) reconstruction using magnetic resonance angiography (MRA) as the evaluation of graft remodeling. Eleven knees that underwent anatomical MPFL reconstruction with the semitendinosus tendon were studied. We evaluated the blood flow around the bone tunnel wall in the arterial phase using MRA approximate 3 months and 1 year after surgery. Clinical and radiological evaluations were also analyzed. MRA showed an inflow vessel into the bone tunnel wall from the medial superior genicular artery on the femoral side, and from the articular branch of the descending genicular artery and the medial superior genicular artery on the patellar side. This contrast effect was decreased at 12 months after surgery in all cases. The clinical scores improved from baseline one year postoperatively. We revealed the blood flow to the bone tunnel wall after anatomical MPFL reconstruction is detected by MRA. The blood flow started within 2 or 3 months postoperatively and was sustained for 12 months. This study supported remodeling of the graft continues 3 months after surgery when the conformity of the patellofemoral joint stabilizes.

Hypoxia promotes differentiation of pure cartilage from human induced pluripotent stem cells.

While cartilage can be produced from induced pluripotent stem cells (iPSCs), challenges such as long culture periods and compromised tissue purity continue to prevail. The present study aimed to determine whether cartilaginous tissue could be produced from iPSCs under hypoxia and, if so, to evaluate its effects on cellular metabolism and purity of the produced tissue. Human iPSCs (hiPSCs) were cultured for cartilage differentiation in monolayers under normoxia or hypoxia (5% O2), and chondrocyte differentiation was evaluated using reverse transcription­quantitative PCR and fluorescence­activated cell sorting. Subsequently, cartilage differentiation of hiPSCs was conducted in 3D culture under normoxia or hypoxia (5% O2), and the formed cartilage­like tissues were evaluated on days 28 and 56 using histological analyses. Hypoxia suppressed the expression levels of the immature mesodermal markers brachyury (T) and forkhead box protein F1; however, it promoted the expression of the chondrogenic markers Acan and CD44. The number of sex­determining region Y­box 9­positive cells and the percentages of safranin O­positive and type 2 collagen­positive tissues increased under hypoxic conditions. Moreover, upon hypoxia­inducible factor (HIF)­1α staining, nuclei of tissues cultured under hypoxia stained more deeply compared with those of tissues cultured under normoxia. Overall, these findings indicated that hypoxia not only enhanced cartilage matrix production, but also improved tissue purity by promoting the expression of HIF­1α gene. Potentially, pure cartilage­like tissues could be produced rapidly and conveniently using this method.

Adsorption mechanisms of inositol hexakisphosphate in the presence of phosphate at the amorphous aluminum oxyhydroxide-water interface.

Myo-inositol hexakisphosphate (myo-IHP) is one of the most common soil organic phosphorus (P) species in soil. Its retention in soil is often competed by phosphate, making bioavailability of P species difficult. In this study, the adsorption mechanism of myo-IHP at the amorphous aluminum (oxyhydr)oxide (AAH)-water interface was investigated at pH 6.5 in the presence of phosphate using batch adsorption experiments and solution 31P NMR spectroscopy. The ratio of [myo-IHP]i/[phosphate]i (Ri) was kept 0.33-3 while ligand addition was varied. In the absence of phosphate, myo-IHP forms inner-sphere surface complexes in AAH via P1,3, P2, P4,6, and P5 functional group coordination. When two ligands were simultaneously added, fewer P functional groups of myo-IHP coordinated to AAH and the surface complexes were altered with the coordination of mainly P1,3 and P2 functional groups. When phosphate was pre-adsorbed, myo-IHP adsorption decreased by 8.0-44% compared to the respective simultaneous addition system. P2 or P5 functional group was predominantly coordinated to the AAH surfaces at Ri = 0.33. Myo-IHP pre-adsorption resulted in an increase in the final myo-IHP adsorption compared to that in the simultaneous addition system under the respective Ri values (0.33-3). In this system, P1,3, P2, P4,6, and P5 functional groups were coordinated to form inner-sphere surface complexes regardless of Ri. The study revealed that the functional group specific adsorption mechanism of myo-IHP at the AAH-water interface was affected by addition sequence and Ri of two ligands. The competitive adsorption between organic P and phosphate plays an important role in the fate of P in soils.

CD81 inhibition with the cytoplasmic RNA vector producing anti-CD81 antibodies suppresses arthritis in a rat CIA model.

OBJECTIVE: Cluster of differentiation 81 (CD81) is a tetraspanin membrane protein consisting of 4 transmembrane domains and 2 outer membrane loops. CD81 inhibition is a potential treatment for rheumatoid arthritis (RA). Here, we investigated the therapeutic effects of the cytoplasmic RNA vector expressing anti-CD81 antibodies (the anti-CD81 vector) on the ankle joint synovium in collagen-induced arthritis (CIA) rats. METHODS: Body weight, paw volume, and clinical scores were measured on days 0, 7, and 10 and daily thereafter. On day 28, the ankle joints of the rats were removed and stained with haematoxylin, eosin, and Safranin O. Arthritic changes such as inflammatory cell infiltration, synovial proliferation, articular cartilage destruction, and bone erosion were evaluated by histological scoring. RESULTS: Symptom onset was delayed in the right lower limbs of the rats administered the cytoplasmic RNA vector (CIA + anti-CD81) compared with that in the control group (CIA + control). The CIA + anti-CD81 rats were heavier than the CIA + control rats. The paw volume and clinical scores were significantly lower in the CIA + anti-CD81 than in the CIA + control. The histological scores indicated significantly milder manifestations of RA in the CIA + anti-CD81 than in the CIA + control. CONCLUSIONS: Administration of the cytoplasmic RNA vector expressing anti-CD81 antibodies suppressed arthritis and joint destruction in CIA rats. Our findings suggest that the cytoplasmic RNA vector can be used to treat RA.

Understanding the Importance of Labile Fe(III) during Fe(II)-Catalyzed Transformation of Metastable Iron Oxyhydroxides.

Transformation of metastable Fe(III) oxyhydroxides is a prominent process in natural environments and can be significantly accelerated by the coexisting aqueous Fe(II) (Fe(II)aq). Recent evidence points to the solution mass transfer of labile Fe(III) (Fe(III)labile) as the primary intermediate species of general importance. However, a mechanistic aspect that remains unclear is the dependence of phase outcomes on the identity of the metastable Fe(III) oxyhydroxide precursor. Here, we compared the coupled evolution of Fe(II) species, solid phases, and Fe(III)labile throughout the Fe(II)-catalyzed transformation of lepidocrocite (Lp) versus ferrihydrite (Fh) at equal Fe(III) mass loadings with 0.2-1.0 mM Fe(II)aq at pH = 7.0. Similar to Fh, the conversion of Lp to product phases occurs by a dissolution-reprecipitation mechanism mediated by Fe(III)labile that seeds the nucleation of products. Though for Fh we observed a transformation to goethite (Gt), accompanied by the transient emergence and decline of Lp, for initial Lp we observed magnetite (Mt) as the main product. A linear correlation between the formation rate of Mt and the effective supersaturation in terms of Fe(III)labile concentration shows that Fe(II)-induced transformation of Lp into Mt is governed by the classical nucleation theory. When Lp is replaced by equimolar Gt, Mt formation is suppressed by opening a lower barrier pathway to Gt by heterogeneous nucleation and growth on the added Gt seeds. The collective findings add to the mechanistic understanding of factors governing phase selections that impact iron bioavailability, system redox potential, and the fate and transport of coupled elements.

Accumulation and release of organic phosphorus (P) from legacy P-affected soils to adjacent drainage water.

Legacy effects of P in agricultural soils have been highlighted in recent literature. However, co-accumulation and release of organic P (Po) have often been ignored in current agro-environmental assessments. The mineralizable Po fraction has a potential to increase the activity of phosphate in pore water, increasing fertility or degrading water quality. In this study, the effects of agricultural management practices (fertilizer applied corn-soybean rotation cropland and dairy manure applied pasture) on the Po/phosphate ratio were investigated in P-rich (290-1232 mg kg-1) agricultural soils and adjacent ditchwater using experimental soil-water chemistry. The effect of agricultural management was significant on both Po and the Po/phosphate ratio in soil and adjacent ditchwater. The Po content, dominated by orthophosphate monoesters, in the manure-amended pasture (average ~ 245 mg kg-1) was significantly greater than that in the fertilizer-applied cropland (average 103 mg kg-1). The Po/phosphate ratio was also significantly greater in the manure-amended pasture (0.54) than in the fertilizer-applied cropland (0.42). Similarly, water quality data also showed that ditchwater near the pasture had a significantly greater flux of dissolved non-reactive P and a greater Po/phosphate ratio compared to the water near the fertilizer-applied sites. Furthermore, a greater Po/phosphate ratio in ditchwater was often observed during wet periods, and the ratio was positively correlated to the discharge (r = 0.42, p = 0.003). The study showed the agricultural management-specific Po accumulation and release and - Po/phosphate ratio that might affect the fate of P in agroecosystems.

Depth sequence distribution of water extractable colloidal phosphorus and its phosphorus speciation in intensively managed agricultural soils.

Legacy phosphorus (P) has accelerated the subsurface transport of colloidal P (CP) in intensively managed agricultural soils in the Midwestern U.S. Because of its high P sorption capacity and mobility, understanding the depth sequence distribution of mobile CP and its speciation in the soil profile is critical in assessing total P (TP) loss to protect the water quality of adjacent water bodies. In this study, physicochemical properties of water-extractable colloids (WECs) from the soil profile at 0-180 cm were characterized using conventional wet chemical analysis. Solution P-31 nuclear magnetic resonance spectroscopy (NMR), P and Fe K-edge X-ray absorption spectroscopy, and transmission electron microscopy were also used to understand P speciation and mineralogy of CP. Percent recovery of WECs per bulk soil increased more than three times with increasing depth. Considering mildly alkaline pH of pore water and negative zeta potential (-21 ± 4 mV) of WECs (size: 1.65 ± 0.45 µm), the transport of P rich WECs (TP: approximately 210-700 mg kg-1) were facilitated from surface to subsoils. Generally, TP in WEC decreased with increasing depth. Interestingly, WECs in subsoil contain organic P (OP) as much as 60 mg kg-1. NMR analysis clearly showed the presence of OP monoesters, OP diesters, and orthophosphate in these particles. Both orthophosphate and OP species interacted with iron oxyhydroxides, calcite, and aluminol functional groups of gibbsite and or phyllosilicates. The study showed the availability of WECs from surface to subsoils that carry orthophosphate as well as OP in legacy P impacted agricultural soils in the Midwestern U.S.