Epigenetic recording of stimulation history reveals BLIMP1-BACH2 balance in determining memory B cell fate upon recall challenge.

Memory B cells (MBCs) differentiate into plasma cells (PCs) or germinal centers (GCs) upon antigen recall. How this decision is programmed is not understood. We found that the relative strength between two antagonistic transcription factors, B lymphocyte-induced maturation protein 1 (BLIMP1) and BTB domain and CNC homolog 2 (BACH2), progressively increases in favor of BLIMP1 in antigen-responding B cells through the course of primary responses. MBC subsets that preferentially produce secondary GCs expressed comparatively higher BACH2 but lower BLIMP1 than those predisposed for PC development. Skewing the BLIMP1-BACH2 balance in otherwise fate-predisposed MBC subsets could switch their fate preferences. Underlying the changing BLIMP1-over-BACH2 balance, we observed progressively increased accessibilities at chromatin loci that are specifically opened in PCs, particularly those that contain interferon-sensitive response elements (ISREs) and are controlled by interferon regulatory factor 4 (IRF4). IRF4 is upregulated by B cell receptor, CD40 or innate receptor signaling and it induces graded levels of PC-specifying epigenetic imprints according to the strength of stimulation. By analyzing history-stamped GC B cells, we found progressively increased chromatin accessibilities at PC-specific, IRF4-controlled gene loci over time. Therefore, the cumulative stimulation history of B cells is epigenetically recorded in an IRF4-dependent manner, determines the relative strength between BLIMP1 and BACH2 in individual MBCs and dictates their probabilities to develop into GCs or PCs upon restimulation.

High recallability of memory B cells requires ZFP318-dependent transcriptional regulation of mitochondrial function.

Expression of the transcriptional regulator ZFP318 is induced in germinal center (GC)-exiting memory B cell precursors and memory B cells (MBCs). Using a conditional ZFP318 fluorescence reporter that also enables ablation of ZFP318-expressing cells, we found that ZFP318-expressing MBCs were highly enriched with GC-derived cells. Although ZFP318-expressing MBCs constituted only a minority of the antigen-specific MBC compartment, their ablation severely impaired recall responses. Deletion of Zfp318 did not alter the magnitude of primary responses but markedly reduced MBC participation in recall. CD40 ligation promoted Zfp318 expression, whereas B cell receptor (BCR) signaling was inhibitory. Enforced ZFP318 expression enhanced recall performance of MBCs that otherwise responded poorly. ZFP318-deficient MBCs expressed less mitochondrial genes, had structurally compromised mitochondria, and were susceptible to reactivation-induced cell death. The abundance of ZFP318-expressing MBCs, instead of the number of antigen-specific MBCs, correlated with the potency of prime-boost vaccination. Therefore, ZFP318 controls the MBC recallability and represents a quality checkpoint of humoral immune memory.

Poly-γ-glutamic acid enhanced the yield and photosynthesis of soybeans by adjusting soil aggregates and water distribution.

BACKGROUND: Poly-γ-glutamic acid (γ-PGA) is employed extensively in agriculture to enhance soil water retention; however, the underlying mechanism by which γ-PGA improves soil structure and soybean productivity in arid regions remains poorly understood. A micro-scale field experiment was conducted in the arid region of northwest China, employing five concentrations of γ-PGA to investigate its impacts on soybean yield, photosynthesis, and water-use efficiency, as well as soil aggregates and water distribution. The five levels of γ-PGA were 0 (CK), 10 (P1), 20 (P2), 40 (P3), and 80 kg ha-1 (P4). RESULTS: The results demonstrated that the application of γ-PGA significantly improved soybean yield, photosynthesis, and chlorophyll content. It resulted in a decrease in soil aggregate content with a maximum diameter of less than 0.053 mm and an increase in the stability of soil aggregates in the uppermost layer of the soil (0-30 cm). The application of γ-PGA significantly increased soil water content, particularly in the uppermost layer of the soil, and effectively reduced water consumption and improving water use efficiency in soybeans. Overall, the P3 treatment exhibited the most pronounced improvement of soybean yield, photosynthesis, water-use efficiency, as well as distribution of soil aggregates and water. The correlation matrix heatmap also revealed a strong correlation between improvement of soybean yield or photosynthesis at various γ-PGA application levels and the enhancement of soil stability or soil water content. CONCLUSION: The multivariate regression analysis revealed that an optimal application level of 46 kg ha-1 γ-PGA could enhance effectively both yield and water use efficiency of soybean in the arid region of northwest China. © 2024 Society of Chemical Industry.

Cu-MOFs with Rich Open Metal and F Sites for Separation of C2H2 from CO2 and CH4.

Herein, we used the 4-fluoro-[1,1'-biphenyl]-3,4',5-tricarboxylic acid (H3fbptc) ligand to design and construct a new metal-organic framework (MOF), [Cu3(fbptc)2(H2O)3]·3NMP (1), which possesses rich accessible metal sites and F functional groups in the porous walls and shows high uptake for C2H2 (119.3 cm3 g-1) and significant adsorption selectivity for C2H2 over CH4 (14.4) and CO2 (3.6) at 298 K and 100 kPa. In particular, for the gas mixtures of C2H2-CH4 and C2H2-CO2, the MOF reveals large breakthrough time ratios (C2H2/CH4 = 13, C2H2/CO2 = 5.9), which are particularly prominent in dynamic breakthrough experiments, also confirming the excellent potential for the practical separation of C2H2 from two-component mixtures (C2H2-CH4 and C2H2-CO2) and even three-component mixtures (C2H2-CO2-CH4).

One Co-MOF with F Active Sites for Separation of C2H2 from CO2, C2H4, and CH4.

Separating acetylene (C2H2) from other light hydrocarbons and carbon dioxide (CO2) mixtures under mild conditions poses significant challenges due to the remarkably similar properties between C2H2 and those gases. For the goal of C2H2 separation, a F-functionalized organic linker, H2F-PyIP = 2-fluorine-5-(4-pyridyl)isophthalic acid, was designed, and the corresponding metal-organic framework (MOF), {[Co2(F-PyIP)2DMF]·4H2O}n (1), was constructed. The MOF with open channels decorated by the active sites of the F groups revealed the exceptional C2H2 uptake and selectivity over CO2, C2H4, and CH4. The breakthrough experiments with different molar ratios of C2H2-C2H4, C2H2-CO2, and other gas mixtures further verified superior separation capacity of the MOF. In particular, the dynamic separation time intervals for gas mixtures (C2H2/CO2 = 1:1, 1:5, 1:10, and 1:20) fell in the range 30-44 min, highlighting the potential of the MOF for tackling the challenging C2H2/CO2 separation process.

Upregulated TNF-α and lactate following ERK-SGK1 activation in the spinal dorsal horn underlies chronic postsurgical pain.

Skin/muscle incision and retraction (SMIR) during surgeries can lead to chronic postsurgical pain (CPSP). The underlying mechanisms are still unclear. In the present study, we showed that SMIR of the thigh induced phosphorylation of extracellular signal-regulated kinase (ERK), followed by serum- and glucocorticoid-inducible kinase-1 (SGK1) activation in the spinal dorsal horn. Intrathecal injection of PD98059, an ERK inhibitor, or GSK650394, a SGK1 inhibitor, significantly attenuated mechanical pain hypersensitivity in SMIR rats. The level of tumor necrosis factor α and lactate in spinal cord was significantly decreased by PD98059 or GSK650394 injection. Furthermore, PD98059 decreased the activation of SGK1 in the spinal dorsal horn. These results indicate that ERK-SGK1 activation followed by proinflammatory mediator release in the spinal dorsal horn underlies CPSP.

Poly-γ-glutamic acid improved biological nitrogen fixation, water-nitrogen productivity, and nitrate residue in cotton/soybean intercropping.

BACKGROUND: Poly-γ-glutamic acid (γ-PGA) can promote crop growth and improve soil properties efficiently. However, the optimal application rate of γ-PGA in legume/non-legume intercropping systems is still unclear. A potted experiment was conducted to investigate the effects of five γ-PGA rates (0%, 0.1%, 0.2%, 0.3%, and 0.4%, represented by CK, P1, P2, P3, and P4, respectively) on biological nitrogen (N) fixation (BNF), water-N productivity, and nitrate distribution in a cotton/soybean intercropping system. RESULTS: The results showed that the growth indicators (plant height, stem diameter, leaf area index, root dry weight, root length) of cotton and soybean increased first and then decreased with increasing γ-PGA rates, and all growth indicators of cotton and soybean showed peaks in P3 and P2 treatments. The stable 15 N isotope method indicated that γ-PGA promoted the BNF capacity of soybean and soil. In particular, the percentage of N derived from the atmosphere (Ndfa) in soybean reached 61.94% in the P2 treatment. Poly-γ-glutamic acid improved the water-N productivity, and the total N partial factor productivity (NPFP) and water productivity (WP) in P3 treatment increased by 23.80% and 43.86% compared with the CK treatment. The γ-PGA mitigation of potential nitrate residue also decreased first and then increased with increasing γ-PGA rates. CONCLUSION: Multivariate regression analysis showed that 0.22% of the optimal γ-PGA application rate could obtain a higher yield and water-N productivity in cotton/soybean intercropping system simultaneously. © 2023 Society of Chemical Industry.

15 N labeling technology reveals enhancement of nitrogen uptake and transfer by root interaction in cotton/soybean intercropping.

BACKGROUND: Biological nitrogen fixation in legumes and their transfer of nitrogen to non-legumes in legume/non-legume intercropping systems are considered to be important for the improvement of productivity. However, research on interspecific interaction and root nitrogen transfer in cotton/soybean intercropping systems has rarely been undertaken. In this study, the roots of cotton and soybean were separated with either complete root barriers (CB), using plastic film, or semi-root barriers (SB), using nylon net. No root barrier (NB) was used as the control. RESULTS: The results showed that cotton produced more above-ground dry matter (DM) than soybean. The above-ground DM and nitrogen uptake of cotton was greatest with the NB treatment. The above-ground DM and nitrogen uptake of soybean was greatest with the CB treatment. At the harvest stage, the nitrogen transfer rate from soybean to cotton was 22.47% with the SB treatment and 40.41% with the NB treatment. Interspecific root interaction increased the nitrogen transfer amount, especially for the cotton roots in the 0-15 cm soil layer and for the soybean roots in the 0-30 cm soil layer. The root distribution of soybean was the key factor affecting nitrogen transfer amount, and nitrogen transfer amount was the key factor affecting nitrogen uptake of cotton in the cotton/soybean intercropping system. CONCLUSION: These results indicated that nitrogen transfer from soybean to cotton through root interaction improved cotton above-ground DM and nitrogen uptake. © 2023 Society of Chemical Industry.

Active Sites Decorated Nonpolar Pore-Based MOF for One-step Acquisition of C2 H4 and Recovery of C3 H6.

Herein, a 2-fold interpenetrated metal-organic framework (MOF) Zn-BPZ-TATB with accessible N/O active sites in nonpolar pore surfaces was reported for one-step C2 H4 purification from C2 H6 or C3 H6 mixtures as well as recovery of C3 H6 from C2 H6 /C3 H6 /C2 H4 mixtures. The MOF exhibits the favorable C2 H6 and C3 H6 uptakes (>100 cm3 g-1 at 298 K under 100 kPa) as well as selective adsorption of C2 H6 and C3 H6 over C2 H4 . The C3 H6 - and C2 H6 -selective feature were investigated detailedly by experimental tests as well as sorption kinetic studyies. Molecular modelling revealed the multiple interactions between C3 H6 or C2 H6 molecules and methyl groups as well as triazine rings in pores. Zn-BPZ-TATB not only can directly generate 323.4 L kg-1 and 15.4 L kg-1 of high-purity (≥99.9 %) C2 H4 from C3 H6 /C2 H4 and C2 H6 /C2 H4 mixtures, but also provide a large high-purity (≥99.5 %) C3 H6 recovery capacity of 60.1 L kg-1 from C3 H6 /C2 H4 mixtures. More importantly, the high-purity C3 H6 (≥99.5 %) and C2 H4 (≥99.9 %) with the productivities of 38.2 and 12.7 L kg-1 can be simultaneously obtained from C2 H6 /C3 H6 /C2 H4 mixtures through a single adsorption/desorption cycle.

An aspartic protease 47 causes quantitative recessive resistance to rice black-streaked dwarf virus disease and southern rice black-streaked dwarf virus disease.

Rice black-streaked dwarf virus disease (RBSDVD) and southern rice black-streaked dwarf virus disease (SRBSDVD) are the most destructive viral diseases in rice. Progress is limited in breeding due to lack of resistance resource and inadequate knowledge on the underlying functional gene. Using genome-wide association study (GWAS), linkage disequilibrium (LD) decay analyses, RNA-sequencing, and genome editing, we identified a highly RBSDVD-resistant variety and its first functional gene. A highly RBSDVD-resistant variety W44 was identified through extensive evaluation of a diverse international rice panel. Seventeen quantitative trait loci (QTLs) were identified among which qRBSDV6-1 had the largest phenotypic effect. It was finely mapped to a 0.8-1.2 Mb region on chromosome 6, with 62 annotated genes. Analysis of the candidate genes underlying qRBSDV6-1 showed high expression of aspartic proteinase 47 (OsAP47) in a susceptible variety, W122, and a low resistance variety, W44. OsAP47 overexpressing lines exhibited significantly reduced resistance, while the knockout mutants exhibited significantly reduced SRBSDVD and RBSDVD severity. Furthermore, the resistant allele Hap1 of OsAP47 is almost exclusive to Indica, but rare in Japonica. Results suggest that OsAP47 knockout by editing is effective for improving RBSDVD and SRBSDVD resistance. This study provides genetic information for breeding resistant cultivars.

Golden 2-like transcription factor contributes to the major QTL against rice black-streaked dwarf virus disease.

KEY MESSAGE: A major resistance QTL was identified on chromosome 6 in rice variety Wuke; both overexpression and knockdown experiments confirmed that OsGLK1 is the candidate gene for association with Rice black-streaked dwarf virus disease. Rice black-streaked dwarf virus disease is one of the most destructive rice viral diseases in China and East Asia. Progress has been limited in RBSDVD resistance breeding due to inadequate knowledge on the underlying functional genes. In this study, a major QTL for RBSDV (rice black-streaked dwarf virus) independent of SBPH (small brown planthopper) resistance was mapped in a 1.8 Mb interval on chromosome 6 by using an F2:3 population originated from resistant rice variety Wuke. Representative transcripts within this region were analysed and three genes showing amino acid sequence variation in functional domains were selected for transformation. Overexpression experiments showed that one gene exhibited significant enhanced resistance compared to control lines, encoding protein involving Myb domain and probable transcription factor Golden 2-like1 (GLK1). Furthermore, OsGLK1 knockdown rice lines were investigated and the resistance ability was significantly declined without this gene compared to the wild type. Taken together, both overexpression and knockdown experiments strongly suggested that OsGLK1 plays an important role for RBSDV resistance and contributes to the major QTL. The study paves the way for elucidating the molecular mechanism underlying RBSDVD resistance and the molecular markers associated with OsGLK1 may be used for marker-assisted selection.

Zinc Accumulation Aggravates Cerebral Ischemia/Reperfusion Injury Through Inducing Endoplasmic Reticulum Stress.

Zinc is highly enriched in the central nervous system. Numerous evidences suggest that high concentration of zinc acts as a critical mediator of neuronal death in the ischemic brain, however, the possible mechanisms of neurotoxicity of zinc during cerebral ischemia/reperfusion (I/R) remain elusive. Endoplasmic reticulum (ER) is a storage location of intracellular zinc. ER stress related genes were up-regulated during zinc-induced neuronal death in vascular-type senile dementia. In the present study, we investigated whether intracellular accumulated zinc aggravates I/R injury through ER stress and ER stress-associated apoptosis. Male Sprague-Dawley rats were subjected to 90 min middle cerebral artery occlusion (MCAO) and received either vehicle or zinc chelator TPEN 15 mg/kg. The expression of ER stress related factors glucose-regulated protein 78 (GRP78) and phosphorylated eukaryotic initiation factor 2α (p-eIF2α), ER stress related apoptotic proteins CCAAT-enhancer-binding protein homologous protein (CHOP) and caspase-12, as well as anti-apoptotic factor B-cell lymphoma-2 (Bcl-2) were assessed 24 h after reperfusion. Our results showed that the levels of GRP78 and p-eIF2α, as well as CHOP and caspase-12, were increased in ischemic brain, indicating that cerebral I/R triggers ER stress. Furthermore, GRP78, CHOP and caspase-12 were all colocalized with the zinc-specific dyes NG, suggesting that there is certain relationship between cytosolic labile zinc and ER stress following cerebral ischemia. Chelating zinc with TPEN reversed the expression of GRP78, p-eIF2α in ischemic rats. Moreover, CHOP and NeuN double staining positive cells, as well as caspase-12 and TUNEL double staining positive cells were also decreased after TPEN treatment, indicating that chelating zinc might inhibit ER stress and decreased ER stress associated neuronal apoptosis. In addition, TPEN treatment reversed the downregulated level of Bcl-2, which localized in the ER membrane and involved in the dysfunction of ER, confirming that the anti-apoptosis effects of chelating zinc following I/R are exerted via inhibition of the ER stress. Taken together, this study demonstrated that excessive zinc activates ER stress and zinc induced neuronal cell death is at least partially due to ER stress specific neuronal apoptosis in ischemic penumbra, which may provide an important mechanism of cerebral I/R injury.

One-Step C2 H4 Purification from Ternary C2 H6 /C2 H4 /C2 H2 Mixtures by a Robust Metal-Organic Framework with Customized Pore Environment.

One-step C2 H4 purification from ternary C2 H6 /C2 H4 /C2 H2 mixtures by a single adsorbent is of great industrial significance, but few adsorbents achieve this separation. Herein, we report a robust metal-organic framework (MOF) that possesses methyl-decorated nonpolar pores and shows one-step C2 H4 purification (purity >99.9 %) from binary C2 H6 /C2 H4 mixtures and ternary C2 H6 /C2 H4 /C2 H2 mixtures. The methyl groups in pores provide a suitable pore environment to simultaneously enhance the adsorption capacity for C2 H2 and C2 H6 compared to C2 H4 . Simulations revealed the multiple interactions between C2 H6 or C2 H2 molecules and the pore wall, while the interactions with C2 H4 molecules are weak and also unfavorable due to the repulsion from methyl groups in pores. The MOF displays high C2 H6 and C2 H2 uptakes and benchmark C2 H6 /C2 H4 selectivity (2.2), surpassing all of the reported MOFs for one-step C2 H4 purification from ternary C2 H6 /C2 H4 /C2 H2 mixtures.

Boosting Ethane/Ethylene Separation by MOFs through the Amino-Functionalization of Pores.

Adsorption technology based on ethane-selective materials is a promising alternative to energy-intensive cryogenic distillation for separating ethane (C2 H6 ) and ethylene (C2 H4 ). We employed a pore engineering strategy to tune the pore environment of a metal-organic framework (MOF) through organic functional groups and boosted the C2 H6 /C2 H4 separation of the MOF. Introduction of amino (-NH2 ) groups into Tb-MOF-76 not only decreased pore sizes but also facilitated multiple guest-host interactions in confined pores. The NH2 -functionalized Tb-MOF-76(NH2 ) has increased C2 H6 and C2 H4 uptakes and C2 H6 /C2 H4 selectivity. The results of experimental and simulated transient breakthroughs reveal that Tb-MOF-76(NH2 ) has significantly improved one-step separation performance for C2 H6 /C2 H4 mixtures with a high C2 H4 (>99.95 %) productivity of 17.66 L kg-1 compared to 7.53 L kg-1 by Tb-MOF-76, resulting from the suitable pore confinement and accessible -NH2 groups on pore surfaces.

Development and validation of a prognostic nomogram in gastric cancer with hepatitis B virus infection.

BACKGROUND: Patients with HBsAg-positive gastric cancer (GC) are a heterogeneous group, and it is not possible to accurately predict the overall survival (OS) in these patients. METHODS: We developed and validated a nomogram to help improve prediction of OS in patients with HBsAg-positive GC. The nomogram was established by a development cohort (n = 245), and the validation cohort included 84 patients. Factors in the nomogram were identified by univariate and multivariate Cox hazard analysis. We tested the accuracy of the nomograms by discrimination and calibration, and plotted decision curves to assess the benefits of nomogram-assisted decisions in a clinical context. Then we evaluated the risk in the two cohort. RESULTS: Significant predictors were age, tumor stage, distant metastases, gamma-glutamyl transpeptidase (GGT) and alkaline phosphatase (ALP). The proportional-hazards model (nomogram) was based on pre-treatment characteristics. The nomogram had a concordance index (C-index) of 0.812 (95% CI 0.762-0.862), which was superior than the C-index of AJCC TNM Stage (0.755, 95% CI 0.702-0.808). The calibration plot in the validation cohort based on 5 predictors suggested good agreement between actual and nomogram-predicted OS probabilities. The decision curve showed that the nomogram in predicting OS is better than that of TNM staging system in all range. Moreover, patients were divided into three distinct risk groups for OS by the nomogram: low risk group, middle risk group and high risk group, respectively. CONCLUSION: This nomogram, using five pre-treatment characteristics, improves prediction of OS in patients with HBsAg-positive gastric cancer. It represents an improvement in prognostication over the current TNM stage. To generalize the use of this nomogram in other groups, additional validation with data from other institutions is required.

Zinc accumulation in mitochondria promotes ischemia-induced BBB disruption through Drp1-dependent mitochondria fission.

High concentration of zinc has been reported to act as a critical mediator of neuronal death in the ischemic brain. Our previous studies showed that labile zinc accumulates in cerebromicrovessels and contributes to blood-brain barrier (BBB) permeability increase after cerebral ischemia. However, the role of mitochondrial zinc in ischemia-induced BBB permeability alteration is still unclear. In this study, we showed that ischemia/reperfusion induced free zinc accumulation in endothelial cells (ECs), resulting in increased generation of reactive oxygen species (ROS) in both cultured ECs and in microvessels isolated from the brain of ischemic rats. Furthermore, we found that zinc was highly accumulated in mitochondria, leading to mitochondrial ROS generation under the ischemic condition. Moreover, zinc overload in mitochondria resulted in the collapse of the network of mitochondria, which was mediated through Dynamin-related protein-1 (Drp-1) dependent mitochondrial fission pathway. Finally, the zinc overload in mitochondria activated matrix metalloproteinase-2 and led to ischemia-induced BBB permeability increase. This study demonstrated that zinc-ROS pathway in mitochondria contributes to the ischemia-induced BBB disruption via Drp-1 dependent mitochondrial fission pathway.

Fluorescence lifetime-based pH sensing by platinum nanoclusters.

In this work, we report for the first time the application of ultrasmall Pt nanoclusters (Pt NCs) as a fluorescence-lifetime-based pH sensor. The fluorescence properties of our prepared Pt NCs show strong pH dependence, due to the change of the surface states of Pt NCs under alkaline/acidic conditions. Interestingly, both the fluorescence intensity and the fluorescence lifetime of Pt NCs exhibit a good linear relationship in the physiologically relevant pH range of 6.02-7.54. Our Pt NC-based pH sensor possesses many important features as an attractive sensor, including high anti-jamming capability, excellent stability and good reversibility. Moreover, the use of fluorescence lifetime as the optical readout signal rather than the intensity makes the present pH sensor more reliable in practical applications because the fluorescence lifetime is invariant to the probe concentration or changes in excitation conditions. Application of the Pt NC-based system for pH detection in real water samples and simulated intracellular environment samples has also been successfully demonstrated.

Nonenzymatic Glucose Sensing and Magnetic Property Based On the Composite Formed by Encapsulating Ag Nanoparticles in Cluster-Based Co-MOF.

Utilizing the oxygen-bridged 5,5'-oxidiisophthalic acid (H4L) linker, one Co(II)-based 3D porous MOF {[Co5(L)2(OH)2(OH2)2(H2O)4]·2DMF·H2O}n (1) with pentanuclear [Co5(µ3-OH)2(µ2-OH2)2]8+ cluster was prepared. The glassy carbon electrode was modified by 1, and the obtained electrode revealed electrocatalytic performance for glucose oxidation. The porous MOF matrix is beneficial for dispersing Ag nanoparticles evenly in the interior cages or channels, so Ag@1 composite composed of both Ag nanoparticles and MOF was further prepared through deposition-reduction method to enhance electrocatalytic activity. The result demonstrates that the glucose oxidation by Ag@1 was greatly increased with low detection limit (1.32 µM) and good selectivity and sensitivity (0.135 µA µM-1), which promote the application of MOF-template porous composites as advanced electrochemical sensor materials. Furthermore, 1 shows an interesting magnetic spin-glass slow dynamics for the existing of peculiar pentanuclear Co(II) clusters.

Pharmacokinetics and pharmacodynamics of cinacalcet in patients with renal failure receiving hemodialysis and hemodiafiltration therapy
.

OBJECTIVE: Few studies have focused on the effects of dialysis on cinacalcet. In addition, there is no data available on hemodiafiltration (HDF) all over the world. Therefore, we studied the pharmacokinetics (PK) and pharmacodynamics (PD) of cinacalcet in patients undergoing hemodialysis (HD) or HDF to provide more guiding information on its use in these patients, especially in China. MATERIALS AND METHODS: In this open-label, single-dose, single-center study of 7 patients with renal failure who underwent dialysis, patients were randomly allocated to two groups consisting of 4 and 3 patients who received low-flux HD and HDF treatments, respectively. All participants underwent dialysis for 4 hours immediately after receiving single oral doses of a 25 mg cinacalcet tablet. High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and electrochemical luminescence (EI) were used to determine the cinacalcet plasma concentrations and intact parathyroid hormone (iPTH) serum levels, respectively. RESULTS: Peak concentration (Cmax) and area under the curve (AUC) from time 0 to 24 hours (AUC0-24h) of the low-flux HD therapy group were 21.8 ± 18.6 ng/mL and 145.3 ± 91.8 ng×h/mL, respectively, which were similar to those of the HDF group (30.9 ± 7.9 ng/mL and 161.6 ± 26.5 ng×h/mL, respectively). iPTH concentrations of the HD therapy group decreased after cinacalcet administration and increased following its clearance. However, iPTH levels of subjects receiving HDF therapy did not change. CONCLUSION: Compared with healthy Chinese subjects, patients with renal failure had a higher Cmax and AUC0-24h, slightly prolonged time to Cmax (tmax) after administration of the same dose of cinacalcet. On HD treatment day, variation trends of iPTH in Chinese patients and healthy subjects were similar and significantly different from that on the HDF treatment day. Considering the high protein binding rate of cinacalcet, this may lead to the great free-drug clearance during HDF treatment.

Synergistic Interaction Between Zinc and Reactive Oxygen Species Amplifies Ischemic Brain Injury in Rats.

Background and Purpose- Although intracellular zinc accumulation has been shown to contribute to neuronal death after cerebral ischemia, the mechanism by which zinc keeps on accumulating to cause severe brain damage remains unclear. Herein the dynamic cause-effect relationships between zinc accumulation and reactive oxygen species (ROS) production during cerebral ischemia/reperfusion are investigated. Methods- Rats were treated with zinc chelator, ROS scavenger, mitochondria-targeted ROS inhibitor, or NADPH oxidase inhibitor during a 90-minute middle cerebral artery occlusion. Cytosolic labile zinc, ROS level, cerebral infarct volume, and neurological functions were assessed after ischemia/reperfusion. Results- Zinc and ROS were colocalized in neurons, leading to neuronal apoptotic death. Chelating zinc reduced ROS production at 6 and 24 hours after reperfusion, whereas eliminating ROS reduced zinc accumulation only at 24 hours. Furthermore, suppression of mitochondrial ROS production reduced the total ROS level and brain damage at 6 hours after reperfusion but did not change zinc accumulation, indicating that ROS is produced mainly from mitochondria during early reperfusion and the initial zinc release is upstream of ROS generation after ischemia. Suppression of NADPH oxidase decreased ROS generation, zinc accumulation, and brain damage only at 24 hours after reperfusion, indicating that the majority of ROS is produced by NADPH oxidase at later reperfusion time. Conclusions- This study provides the direct evidence that there exists a positive feedback loop between zinc accumulation and NADPH oxidase-induced ROS production, which greatly amplifies the damaging effects of both. These findings reveal that different ROS-generating source contributes to ischemia-generated ROS at different time, underscoring the critical importance of spatial and temporal factors in the interaction between ROS and zinc accumulation, and the consequent brain injury, after cerebral ischemia/reperfusion.