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Various small molecules have been used as functional probes for tissue imaging in medical diagnosis and pharmaceutical drugs for disease treatment. The spatial distribution, target selectivity, and diffusion/excretion kinetics of small molecules in structurally complicated specimens are critical for function. However, robust methods for precisely evaluating these parameters in the brain have been limited. Herein, we report a new method termed “fixation-driven chemical cross-linking of exogenous ligands (FixEL), ” which traps and images exogenously administered molecules of interest (MOIs) in complex tissues. This method relies on protein-MOI interactions and chemical cross-linking of amine-tethered MOI with paraformaldehyde used for perfusion fixation. FixEL is used to obtain images of the distribution of the small molecules, which addresses selective/nonselective binding to proteins, time-dependent localization changes, and diffusion/retention kinetics of MOIs such as the scaffold of PET tracer derivatives or drug-like small molecules., ホルマリン漬けから着想した小分子可視化法 --医薬品開発効率化につながる新たな戦略--. 京都大学プレスリリース. 2022-12-05.

Neurotransmitter receptors are regulated by an extensive and dynamic network of protein-protein interactions. Understanding how these networks control synaptic transmission and give rise to higher-order brain functions necessitates their investigation in the live mammalian brain. However, tools available for this purpose lack the temporal resolution necessary to capture rapid changes in the interactome in live animals and require potentially disruptive genetic modifications to the animal under study. Here, we describe a method for light-activated proximity labelling in the live mouse brain that relies solely on small-molecule reagents and achieves a minute-order temporal resolution. Named PhoxID (photooxidation-driven proximity labelling for protein identification), this method involves selectively tethering a chemical photosensitiser to neurotransmitter receptors of interest and enabled us to identify characteristic as well as less studied interactors of the endogenous alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) and the gamma-aminobutyric acid type A receptor (GABAAR) with just minutes of in-brain green light irradiation. Furthermore, PhoxID's temporal precision allowed us to capture molecular snapshots of the AMPAR-proximal proteome in the postnatal developing cerebellum, leading to the discovery of age-dependent shifts. Overall, this work establishes a highly flexible and generalisable platform to study receptor interactomes and proximal microenvironments in genetically intact specimens with an unprecedented temporal resolution.

Neurotransmitter receptors are essential components of synapses for communication between neurons in the brain. Because the spatiotemporal expression profiles and dynamics of neurotransmitter receptors involved in many functions are delicately governed in the brain,in vivoresearch tools with high spatiotemporal resolution for receptors in intact brains are highly desirable. Covalent chemical labelling of proteins without genetic manipulation is now a powerful method for analyzing receptorsin vitro. However, selective target receptor labelling in the brain has not yet been achieved. This study shows that ligand-directed alkoxyacylimidazole (LDAI) chemistry can be used to selectively tether synthetic probes to target endogenous receptors in living mouse brains. The reactive LDAI reagents with negative charges were found to diffuse well over the whole brain and could selectively label target endogenous receptors, including AMPAR, NMDAR, mGlu1, and GABAAR. This simple and robust labelling protocol was then used for various applications: three-dimensional spatial mapping of endogenous receptors in the brains of healthy and disease-model mice; multi-colour receptor imaging; and pulse-chase analysis of the receptor dynamics in postnatal mouse brains. Here, results demonstrated that bioorthogonal receptor modification in living animal brains may provide innovative molecular tools that contribute to the in-depth understanding of complicated brain functions.

To mitigate global warming and the serious problems incurred by the disposal of petroleum-based plastics, it is important to develop derivatives of biomass materials that can be used as substitutes. To overcome the lack of thermoplasticity of wood, a wet extrusion molding process for wood powder using a cellulose derivative, hydroxypropylmethyl cellulose (HPMC), had been developed. However, this material quickly reabsorbed water, swelled, and disintegrated in liquid. In the present study, a natural organic acid, citric acid, was added and kneaded together with the wood powder, the HPMC, and water. The resultant clay-like material was extruded into a tube-shaped material. The tube was air-dried and heated at 180 °C for 5 min to 30 min to allow crosslinking. By heating 1% citric acid for 30 min, the material avoided disintegrating in water for 60 min. The addition of 3% citric acid with 30 min crosslinking gave the material water resistance in water for 12 h. The degradability in the water was found to be controllable by changing the amount of citric acid and the heating time. This is a novel result because wood can be molded into a practical three-dimensional (3D) biomass composite material using this technology with natural substances without relying on petroleum-based plastics.

Nuclear hyperpolarization has emerged as a method to dramatically enhance the sensitivity of NMR spectroscopy. By application of this powerful tool, small molecules with stable isotopes have been used for highly sensitive biomedical molecular imaging. The recent development of molecular probes for hyperpolarized in vivo analysis has demonstrated the ability of this technique to provide unique metabolic and physiological information. This review presents a brief introduction of hyperpolarization technology, approaches to the rational design of molecular probes for hyperpolarized analysis, and examples of molecules that have met with success in vitro or in vivo.

Dynamic nuclear polarization (DNP) is an emerging cutting-edge method of acquiring metabolic and physiological information in vivo. We recently developed γ-glutamyl-[1-13C]glycine (γ-Glu-[1-13C]Gly) as a DNP nuclear magnetic resonance (NMR) molecular probe to detect γ-glutamyl transpeptidase (GGT) activity in vivo. However, the detailed enzymatic and magnetic properties of this probe remain unknown. Here, we evaluate a γ-Glu–Gly scaffold and develop a deuterated probe, γ-Glu-[1-13C]Gly-d2, that can realize a longer lifetime of the hyperpolarized signal. We initially evaluated the GGT-mediated enzymatic conversion of γ-Glu–Gly and the magnetic properties of 13C-enriched γ-Glu–Gly (γ-Glu-[1-13C]Gly and γ-[5-13C]Glu–Gly) to support the validity of γ-Glu-[1-13C]Gly as a DNP NMR molecular probe for GGT. We then examined the spin-lattice relaxation time (T1) of γ-Glu-[1-13C]Gly and γ-Glu-[1-13C]Gly-d2 under various conditions (D2O, PBS, and serum) and confirmed that the T1 of γ-Glu-[1-13C]Gly and γ-Glu-[1-13C]Gly-d2 was maintained for 30 s (9.4 T) and 41 s (9.4 T), respectively, even in serum. Relaxation analysis of γ-Glu-[1-13C]Gly revealed a significant contribution of the dipole–dipole interaction and the chemical shift anisotropy relaxation pathway (71% of the total relaxation rate at 9.4 T), indicating the potential of deuteration and the use of a lower magnetic field for realizing a longer T1. In fact, by using γ-Glu-[1-13C]Gly-d2 as a DNP probe, we achieved longer retention of the hyperpolarized signal at 1.4 T.

Protein analysis under biological conditions is now regarded as indispensable for understanding the structure and function of proteins, in addition to in vitro studies using purified target proteins. Because there are many molecules other than the protein-of-interest (POI) under live cell conditions, selective labeling of a POI is critical to distinguish the POI from other proteins for precise analysis. Protein labeling strategies utilizing genetically encoded tags have been used in POI modification in the complex environment of live cells. However, genetic manipulation may often induce overexpression of the POI and/or perturb the cellular context, resulting in unexpected artifacts in the protein analysis. Alternatively, recent progress in chemical biology has produced two major chemical approaches for analyzing endogenous proteins under native conditions. In this review, we summarize these techniques that utilize either protein-selective chemical labeling or proteome-directed chemical modification.

Introduction: Combination therapy with peritoneal dialysis and hemodialysis (PD+HD) is widely used for PD patients with decreased residual kidney function in Japan; however, hospitalization for this combined dialysis has not been investigated so far. We compared the risk of hospitalization for PD+HD with that for HD. Methods: A multicenter, prospective observational study was conducted on 42 PD+HD and 42 HD patients matched for age and diabetic nephropathy. The main outcome measure was the cumulative incidence of hospitalization for any cause assessed with the Kaplan-Meier method. Hospitalization rates (the number of admissions per 100 patient-years) associated with dialysis modality were also calculated. The impact of dialysis modality on time to hospitalization was analyzed using the Cox proportional hazard model. Results: There was no significant difference between groups in terms of age, sex, dialysis vintage, diabetic nephropathy, and comorbidities. The cumulative incidence of hospitalization did not significantly differ between the groups (log-rank test, P = 0.36). Although total hospitalization rates were 66.0 in PD+HD and 59.2 in HD, hospitalization rates for the sum of PD-related infections (a composite of catheter-related infection and peritonitis) and vascular access troubles were 21.7 in PD+HD and 7.2 in HD. On univariate Cox proportional hazard analysis, dialysis modality had no significant impact on time to hospitalization. Conclusion: The risk of hospitalization was not significantly different between PD+HD and HD, although PD+HD patients had a higher risk of dialysis access–related complications than HD patients. Keywords: cardiovascular event, combined dialysis, end-stage renal disease (ESRD), PD+HD, residual kidney function (RKF), survival

Birch wood meal was added to the ionic liquid 1-ethyl-3-methylimidazolium acetate ([Emim][OAc])/dimethyl sulfoxide (DMSO) to investigate the conditions required for the complete dissolution of the lignocellulose. Cellulose was treated with [Emim][OAc], and its molecular weight distribution was analyzed by size exclusion chromatography as a model compound. The solubilities of lignocellulose were compared under different treatment conditions, such as the ball-milling time of the raw material and the temperature of the [Emim][OAc]/DMSO treatment. The insoluble fraction was analyzed by pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) to investigate the lignin structure. Cellulose treated with [Emim][OAc] under a nitrogen atmosphere for 1 to 12 h was remarkably depolymerized. It was demonstrated that lignocellulose is easily dissolved when the temperature of [Emim][OAc]/DMSO and the ball-milling times of lignocellulose are increased; a ball-milled sample was completely dissolved in the ionic liquid. The well-dissolved sample had a low cellulose molecular weight. Ball-milling reduced the primary particle size of the sample and facilitated the dissolution and extraction of guaiacyl lignin units.

To date, concentrated sulfuric acid hydrolysis is the most effective process to recover the maximum yield of monomeric sugars from woody biomass because concentrated sulfuric acid can completely swell and hydrolyze cellulose. During this process, sulfuric acid lignin is quantitatively produced as a by-product, which is difficult to use because of self-condensation between the lignin molecules under acidic conditions. In this study, to achieve a high yield of both sugars and lignin, we aimed to valorize the lignin with a unique additive, t-butyl alcohol, in the concentrated sulfuric acid hydrolysis of softwood. When t-butyl alcohol was added, sugar yields were unchanged and were nearly equal to the amount of compositional sugars. Thermoplastic lignin with good solubility in acetone was successfully recovered in a yield higher than 40%. The economic efficiency of the concentrated acid hydrolysis was significantly improved by upgrading the lignin. Thus, this unique process could be a new candidate in the realization of sugar platform biorefineries.

Dissolution-dynamic nuclear polarization (d-DNP) is a state-of-the-art technology that can dramatically enhance the detection sensitivity of nuclear magnetic resonance (NMR). DNP NMR has been applied to small molecules with stable isotopes and has been used to obtain metabolic and physiological information in vivo. However, the hyperpolarized state exponentially decays back to the thermal equilibrium state, depending on the spin-lattice relaxation time (T1). This signal decay has remained a major problem associated with this technology. Therefore, DNP NMR molecular probes useful for in vivo analysis have been limited to naturally occurring small molecules that inherently show long T1. While peptides are promising targets for DNP NMR studies, because of the limitation in T1, DNP NMR molecular probes applicable in vivo have been limited to amino acids or dipeptides. Herein we propose a 13C-labeling strategy to utilize the C-terminal [1-13C]Gly-d2 residue for realizing long T1 in peptides. Structure-based T1 relaxation analysis of amino acids and peptides revealed that (1) T1 does not decrease monotonically with increasing molecular weight and (2) T1 is not significantly affected by a side chain on the neighboring amino acid residue. These findings suggest that the C-terminal [1-13C]Gly-d2 residue affords sufficiently long T1 for biological uses, even in oligopeptides, and allowed us to develop 13C-b- casomorphin-5 (Tyr-Pro-Phe-Pro-[1-13C]Gly-d2, T1 = 24 ± 4 s at 3 T in H2O) and 13C-glutathione (g-Glu-Cys-[1-13C]Gly-d2, T1 = 58 ± 3 s at 3 T in H2O) as DNP NMR probes with long T1. We succeeded in in vivo detection of enzymatic conversions of these two probes. These results demonstrate the utility of our strategy and would contribute to further expansion of the substrate scope for DNP applications.

Dissolution-dynamic nuclear polarization (d-DNP) is a state-of-the-art technology that can dramatically enhance the detection sensitivity of nuclear magnetic resonance (NMR). DNP NMR has been applied to small molecules with stable isotopes and has been used to obtain metabolic and physiological information in vivo. However, the hyperpolarized state exponentially decays back to the thermal equilibrium state, depending on the spin-lattice relaxation time (T1). This signal decay has remained a major problem associated with this technology. Therefore, DNP NMR molecular probes useful for in vivo analysis have been limited to naturally occurring small molecules that inherently show long T1. While peptides are promising targets for DNP NMR studies, because of the limitation in T1, DNP NMR molecular probes applicable in vivo have been limited to amino acids or dipeptides. Herein we propose a 13C-labeling strategy to utilize the C-terminal [1-13C]Gly-d2 residue for realizing long T1 in peptides. Structure-based T1 relaxation analysis of amino acids and peptides revealed that (1) T1 does not decrease monotonically with increasing molecular weight and (2) T1 is not significantly affected by a side chain on the neighboring amino acid residue. These findings suggest that the C-terminal [1-13C]Gly-d2 residue affords sufficiently long T1 for biological uses, even in oligopeptides, and allowed us to develop 13C-β-casomorphin-5 (Tyr-Pro-Phe-Pro-[1-13C]Gly-d2, T1 = 24 ± 4 s at 3 T in H2O) and 13C-glutathione (γ-Glu-Cys-[1-13C]Gly-d2, T1 = 58 ± 3 s at 3 T in H2O) as DNP NMR probes with long T1. We succeeded in in vivo detection of enzymatic conversions of these two probes. These results demonstrate the utility of our strategy and would contribute to further expansion of the substrate scope for DNP applications.

Proteins play central roles in numerous biological events in all living organisms. Notably, the subcellular localization, trafficking, and dynamic alteration of proteins have a crucial impact on cellular functions and fates. To date, scientists have explored a large number of strategies to profile protein characteristics under native conditions. Chemical proteomics is one of the most powerful strategies, offering convenient and efficient profiling of a proteome of interest. Herein, we review the recent progress in subcellular-compartment-focused chemical proteomics approaches, which do not rely on the conventional subcellular fractionation method. Recently, methods for proximity labeling using genetically engineered enzymes have been developed for proteome analysis within organelles and even sub-organelles. In parallel, a few powerful chemical proteomics methods have been invented for subcellular-compartment-focused protein profiling. Organelle-localizable reactive molecules have been designed that can selectively chemically tag proteins localized in the nucleus, mitochondria, and endoplasmic reticulum. A photoactivatable proximity labeling method has also been reported for identifying organellar proteomes with high spatiotemporal resolution. Additionally, a conditional proteomics approach has been used to elucidate proteomes involved in specific microenvironments or processes, such as Zn2+ homeostasis and NO-, and H2O2-rich micro-spaces in live cells.

Various small molecules have been used as functional probes for tissue imaging in medical diagnosis and pharmaceutical drugs for disease treatment. The spatial distribution, target selectivity, and diffusion/extrusion kinetics of small molecules in structurally complicated specimens are critical for function. However, robust methods for precisely evaluating these parameters in the brain have been limited. Herein we report a new method termed “Fixation-driven chemical crosslinking of exogenous ligands (FixEL)” which traps and images exogenously administered molecules-of-interest (MOI) in complex tissues. This method relies on proteins-MOI interactions, and chemical crosslinking of amine-tethered MOI with paraformaldehyde used for perfusion fixation. FixEL is used to obtain images of the distribution of the small molecules and their dynamics, which addresses selective/nonselective binding to proteins, time-dependent localization changes, and diffusion/retention kinetics of MOI such as PET tracer derivatives or drug-like small molecules. Clear imaging of a nanobody distributed in the whole brain was also achieved with high spatial resolution using 2D/3D mode.

Direct activation of cell-surface receptors is highly desirable for elucidating their physiological roles. A potential approach for cell-type-specific activation of a receptor subtype is chemogenetics, in which both point mutagenesis of the receptors and designed ligands are used. However, ligand-binding properties are affected in most cases. Here, we developed a chemogenetic method for direct activation of metabotropic glutamate receptor 1 (mGlu1), which plays essential roles in cerebellar functions in the brain. Our screening identified a mGlu1 mutant, mGlu1(N264H), that was activated directly by palladium complexes. A palladium complex showing low cytotoxicity successfully activated mGlu1 in mGlu1(N264H) knock-in mice, revealing that activation of endogenous mGlu1 is sufficient to evoke the critical cellular mechanism of synaptic plasticity, a basis of motor learning in the cerebellum. Moreover, cell-type-specific activation of mGlu1 was demonstrated successfully using adeno-associated viruses in mice, which shows the potential utility of this chemogenetics for clarifying the physiological roles of mGlu1 in a cell-type-specific manner., 【研究成果】脳組織において狙った細胞の神経伝達物質受容体の活性化に成功 --記憶・学習のメカニズム解明に期待--. 京都大学プレスリリース. 2022-06-17.

Direct activation of cell-surface receptors is highly desirable for elucidating the physiological roles of receptors. However, subtype-selective ligands are very limited because of the high homology among receptor subtypes. A potential approach for selective activation of a receptor subtype is chemogenetics, in which both point mutagenesis of the receptors and designed ligands are used. However, ligand-binding properties are affected in most current methods. Here, we developed a chemogenetic method for direct activation of metabotropic glutamate receptor 1 (mGlu1), which plays essential roles in cerebellar functions in the brain. Our screening identified a mGlu1 mutant, mGlu1(N264H), that was directly activated by palladium complexes. Notably, a palladium complex showing low cytotoxicity successfully activated mGlu1 in mGlu1(N264H) knock-in mice, revealing that activation of endogenous mGlu1 is sufficient to evoke the critical cellular mechanism of synaptic plasticity, a basis of motor learning in the cerebellum.

Serine hydroxymethyltransferase (SHMT) is an enzyme that catalyzes the reaction that converts serine to glycine. It plays an important role in one-carbon metabolism. Recently, SHMT has been shown to be associated with various diseases. Therefore, SHMT has attracted attention as a biomarker and drug target. However, the development of molecular probes responsive to SHMT has not yet been realized. This is because SHMT catalyzes an essential yet simple reaction; thus, the substrates that can be accepted into the active site of SHMT are limited. Here, we focus on the SHMT-catalyzed retro-aldol reaction rather than the canonical serine–glycine conversion and succeed in developing fluorescent and 19F NMR molecular probes. Taking advantage of the facile and direct detection of SHMT, the developed fluorescent probe is used in the high-throughput screening for human SHMT inhibitors, and two hit compounds are obtained., The enzyme serine hydroxymethyltransferase (SHMT) has been implicated in several diseases, however is hard to investigate. Here, the authors used a design strategy based on the retro-aldol-type reaction catalyzed by SHMT to develop SHMT-responsive fluorescence and 19F NMR molecular probes.

In order to fractionate woody biomass, particularly focusing on the recovery of useful lignin, softwood and hardwood wood meal were impregnated with p-cresol or 2,6-xylenol in advance. Dilute acid hydrolysis of monophenol-impregnated wood meal with 1.1% sulfuric acid at 130 °C for 180 min separated hemicellulose-derived sugars for both softwood and hardwood. Thereafter, soda cooking with 0.5 N sodium hydroxide at 150 °C for 90 min delignified hardwood effectively to produce cellulose with a low lignin content; however, resulted in cellulosic pulp with a 50% lignin content for softwood. Lignin was recovered in higher yields and most became soluble in tetrahydrofuran and flowable with heat because lignin self-condensation was successfully prevented under acid hydrolysis by impregnated monophenols. 2,6-Xylenol was more effective than p-cresol. The prehydrolysis-soda cooking process with monophenols could potentially provide functional materials from cellulose, hemicellulose, and lignin without using sulfur.

Summary Bile acids are metabolites of cholesterol that facilitate lipid digestion and absorption in the small bowel. Bile acids work as agonists of receptors to regulate their own metabolism. Bile acids also regulate other biological systems such as sugar metabolism, intestinal multidrug resistance, and adaptive immunity. However, numerous physiological roles of bile acids remain undetermined. In this study, we solved the crystal structure of human serine hydroxymethyltransferase (hSHMT) in complex with an endogenous secondary bile acid glycine conjugate. The specific interaction between hSHMT and the ligand was demonstrated using mutational analyses, biophysical measurements, and structure-activity relationship studies, suggesting that secondary bile acid conjugates may act as modulators of SHMT activity., Graphical abstract, Highlights • The crystal structures of hSHMT in complex with secondary bile acid glycine conjugate • Specific interactions between hSHMT and secondary bile acid conjugate were validated • Biological role of bile acids as modulators for one-carbon metabolism is suggested, Molecular Interaction; Structural Biology; Metabolic Engineering

Overhydration is a major cause of technique failure of peritoneal dialysis (PD). Hence, we investigated the impact of ultrafiltration (UF) volume by once-weekly hemodialysis (HD), excess volume beyond their dry weight, on technique survival of PD and HD combination therapy (PD+HD). Forty-six anuric PD+HD patients were divided into three groups according to baseline UF volume by HD: low-UF (

SA-BDPA is a water-soluble, narrow-line width radical previously used for dynamic nuclear polarization (DNP) signal enhancement in solid-state magic angle spinning NMR spectroscopy. Here, we report the first study using SA-BDPA under dissolution DNP conditions (6.7 T and 1.15 K). Longitudinal-detected (LOD)-electron spin resonance (ESR) and 13C DNP measurements were performed on samples containing 8.4 M [13C]urea dissolved in 50:50 water:glycerol (v/v) doped with either 60 or 120 mM SA-BDPA. Two distinct DNP mechanisms, both "pure"thermal mixing and a well-resolved solid effect could clearly be identified. The radical's ESR line width (30-40 MHz), broadened predominantly by dipolar coupling, excluded any contribution from the cross effect. Microwave frequency modulation increased the enhancement by DNP at the lower radical concentration but not at the higher radical concentration. These results are compared to data acquired with trityl radical AH111501, highlighting the unusual 13C DNP properties of SA-BDPA.

Dynamic nuclear polarization (DNP) is a technique to polarize the nuclear spin population. As a result of the hyperpolarization, the NMR sensitivity of the nuclei in molecules can be dramatically enhanced. Recent application of the hyperpolarization technique has led to advances in biochemical and molecular studies. A major problem is the short lifetime of the polarized nuclear spin state. Generally, in solution, the polarized nuclear spin state decays to a thermal spin equilibrium, resulting in loss of the enhanced NMR signal. This decay is correlated directly with the spin-lattice relaxation time T1 . Here we report [13 C,D14 ]tert-butylbenzene as a new scaffold structure for designing hyperpolarized 13 C probes. Thanks to the minimized spin-lattice relaxation (T1 ) pathways, its water-soluble derivative showed a remarkably long 13 C T1 value and long retention of the hyperpolarized spin state.

Dilute acid hydrolysis is typically conducted on wood to hydrolyze cellulose and hemicellulose into their compositional sugars, furfurals, or organic acids. However, lignin obtained in this process, also called hydrolysis lignin, cannot be generally used as a functional material. To overcome uncontrolled self-condensation of lignin, wood meal was impregnated with a small amount of p-cresol, and then, acid hydrolysis was performed with 1.1% sulfuric acid at 180 °C for 60 min. The cresol hardly changed the main products in the hydrolysate: glucose, formic acid, and levulinic acid. Much larger amount of lignin was extracted from the hydrolysis residue with tetrahydrofuran or by soda cooking than in the process without p-cresol impregnation. It seemed that the impregnated p-cresol was covalently bonded to lignin during acid hydrolysis and successfully prevented the self-condensation of lignin molecules, contributing improvement of the solubility of the resultant lignin in organic solvents or aqueous sodium hydroxide. Our hydrolysis process balances the valorization of carbohydrate with that of lignin.

Hyperpolarization is an emerging method that dramatically enhances NMR signal intensity. As a result of their increased sensitivity, hyperpolarized (HP) NMR molecular probes can be used to perform time-resolved spectroscopy and imaging in vitro and in vivo. It is, however, challenging to design such probes de novo. Herein, the [1-13 C]α-amino acid is reported as a scaffold structure to design HP 13 C NMR molecular probes. The [1-13 C]α-amino acid can be converted to various HP 13 C chemical probes that show sufficient chemical shift change by altering the chemical state of the α nitrogen upon interaction with the target. Several previously reported HP probes could be explained by this design principle. To demonstrate the versatility of this approach, two α-amino-acid-based HP 13 C chemical probes, sensitive to pH and Ca2+ ion, were developed and used to detect targets.

Dynamic nuclear polarization with photo-excited triplet electrons (Triplet-DNP) is demonstrated using 6,13-diphenylpentacene (DPPentacene). DPPentacene is soluble in various organic solvents, while pentacene, which is used in most of the triplet-DNP experiments, has limited solubility. An enhancement factor of 81 is obtained for 1H spins in the glass of ethanol-d6 : water = 80 : 20 (w/w) doped with 0.1 mM DPPentacene at 90 K in 0.67 T.

Combination therapy with peritoneal dialysis and hemodialysis (PD+HD) is widely used in Japan for PD patients with decreased residual renal function. However, fluid status in PD+HD patients has not been well studied. In this cross-sectional study, we compared fluid status in 41 PD+HD patients with that in 103 HD and 92 PD patients using the bioimpedance spectroscopy. Extracellular water normalized to patient height (NECW, kg/m) was the highest in pre-HD (8.3 ± 1.6) followed by PD (7.9 ± 2.7), PD+HD (7.5 ± 2.5), and post-HD patients (6.9 ± 1.5) (P < 0.01). By multiple linear regression analysis, PD+HD was associated with a significantly lower NECW than pre-HD (β = -0.8, P = 0.03) and similar to PD (β = -0.5, P = 0.24) and post-HD (β = 0.6, P = 0.08) after adjustment for age, sex, diabetic nephropathy, ischemic heart disease, dialysis period, and daily urine volume. There was no correlation between NECW and daily urine volume in all dialysis groups. Average daily fluid removal (a sum of urine volume and ultrafiltration volume by dialysis) was positively correlated with NECW in PD+HD and pre-HD, but not in PD and post-HD patients. Our results suggest that fluid status in PD+HD patients with decreased residual renal function is acceptable as compared with that in HD and PD patients.

Parahydrogen-induced polarization (PHIP) is a rapid and cost-effective hyperpolarization technique using transition metal-catalysed hydrogenation with parahydrogen. We examined rhodium catalysts and their kinetic studies, rarely considered in the research of current PHIP. It emerged that rhodium complexes with electron-donating bisphosphine ligands, with a dicyclohexylphosphino group, appear to be more effective than conventional rhodium catalysts.

Lignocresol was isolated from softwood with p-cresol using sulfuric acid and phase separation. An alkaline treatment of the lignocresol, followed by acidification, selectively yielded a guaiacyl coumaran, G1, in the acid-soluble fraction. With further alkaline treatment of G1 in 0.5 M of NaOH solution at 170 °C for 60 min, it was strongly suggested that a guaiacyl benzofuran derivative, G2, was obtained by the elimination of formaldehyde, based on analytical data of the reaction mixture. The process is very unique and well-designed based on the reactivity of Cα-ethers, or Cα-OH, Cβ-aryl-ethers, and Cγ-OH of lignin, although condensation reactions via formaldehyde occurred in parallel to give condensed products with a diarylmethane structure. Because these phenolic dimers, G1 and G2, were recovered from the guaiacyl unit linked with the neighboring guaiacyl units via two Beta-aryl-ether bonds, they are promising lignin-derived chemicals that are obtainable in a high yield.

Hardwood lignin in eucalyptus was first converted to hardwood lignocresol through a phase separation process utilizing wood meal, sulfuric acid, and p-cresol at ambient temperature. A syringyl methyl benzofuran, S2 was selectively obtained via a syringyl-type phenolic dimer with a coumaran ring, S1 by NaOH treatments of hardwood lignocresol at 170 °C. Our process controls the reactivity of Cα linkages, Cβ-aryl-ethers, and Cγ-OH in sequence, successfully resulting in a high yield of specific aromatic chemicals from hardwood lignin based on the successiveness of Cβ-aryl-ethers between syringyl units.