Quantitative Analysis and Manipulation of Alkali Metal Cations at the Cathode Surface in Membrane Electrode Assembly Electrolyzers for CO₂ Reduction Reactions

Kato S., Ito S., Nakahata S., et al. Quantitative Analysis and Manipulation of Alkali Metal Cations at the Cathode Surface in Membrane Electrode Assembly Electrolyzers for CO₂ Reduction Reactions. ChemSusChem, (2024); https://doi.org/10.1002/cssc.202401013.The stable operation of the CO₂ reduction reaction (CO₂RR) in membrane electrode assembly (MEA) electrolyzers is known to be hindered by the accumulation of bicarbonate salt, which are derived from alkali metal cations in anolytes, on the cathode side. In this study, we conducted a quantitative evaluation of the correlation between the CO₂RR activity and the transported alkali metal cations in MEA electrolyzers. As a result, although the presence of transported alkali metal cations on the cathode surface significantly contributes to the generation of C₂₊ compounds, the rate of K⁺ ion transport did not match the selectivity of C₂₊, suggesting that a continuous supply of high amount of K⁺ to the cathode surface is not required for C₂₊ formation. Based on these findings, we achieved a faradaic efficiency (FE) and a partial current density for C₂₊ of 77 % and 230 mA cm⁻², respectively, even after switching the anode solution from 0.1 M KHCO₃ to a dilute K⁺ solution (<7 mM). These values were almost identical to those when 0.1 M KHCO₃ was continuously supplied. Based on this insight, we successfully improved the durability of the system against salt precipitation by intermittently supplying concentrated KHCO₃, compared with the continuous supply

Marmoset Cytochrome P450 3A4 Ortholog Expressed in Liver and Small-Intestine Tissues Efficiently Metabolizes Midazolam, Alprazolam, Nifedipine, and Testosterone

ABSTRACT Common marmosets (Callithrix jacchus), small New World primates, are increasingly attracting attention as potentially useful animal models for drug development. However, characterization of cytochrome P450 (P450) 3A enzymes involved in the metabolism of a wide variety of drugs has not investigated in marmosets. In this study, sequence homology, tissue distribution, and enzymatic properties of marmoset P450 3A4 ortholog, 3A5 ortholog, and 3A90 were investigated. Marmoset P450 3A forms exhibited high amino acid sequence identities (88-90%) to the human and cynomolgus monkey P450 3A orthologs and evolutionary closeness to human and cynomolgus monkey P450 3A orthologs compared with other P450 3A enzymes. Among the five marmoset tissues examined, P450 3A4 ortholog mRNA was abundant in livers and small intestines where P450 3A4 ortholog proteins were immunologically detected. Three marmoset P450 3A proteins heterologously expressed in Escherichia coli membranes catalyzed midazolam 19-and 4-hydroxylation, alprazolam 4-hydroxylation, nifedipine oxidation, and testosterone 6b-hydroxylation, similar to cynomolgus monkey and human P450 3A enzymes. Among the marmoset P450 3A enzymes, P450 3A4 ortholog effectively catalyzed midazolam 19-hydroxylation, comparable to microsomes from marmoset livers and small intestines. Correlation analyses with 23 individual marmoset liver microsomes suggested contributions of P450 3A enzymes to 19-hydroxylation of both midazolam (human P450 3A probe) and bufuralol (human P450 2D6 probe), similar to cynomolgus monkey P450 3A enzymes. These results indicated that marmoset P450 3A forms had functional characteristics roughly similar to cynomolgus monkeys and humans in terms of tissue expression patterns and catalytic activities, suggesting marmosets as suitable animal models for P450 3A-dependent drug metabolism

Effects of Green Tea Fractions on Oxygen-Induced Retinal Neovascularization in the Neonatal Rat

This study aimed to investigate the preventive effects of green tea fractions (GTFs) on rat model of oxygen-induced retinopathy (OIR). Neonatal Sprague-Dawley rats were exposed to daily cycles of 80% oxygen (20.5 h), ambient air (0.5 h), and progressive return to 80% oxygen (3 h) until postnatal day 12 (P12), then the rats were placed in ambient air until P18. The green tea was fractionated by DM-A50, DM-W, M-B, and M-W. The rats were treated once daily from P6 to P17 by gastric gavage of GTFs (0.05 or 0.01 g/ml) or distilled water (DW) at 50 µl/10 g body weight. On P18, the rats were sacrificed and the retinal samples were collected. The retinal neovascularization (NV) was scored and avascular areas (AVAs) were measured as a % of total retinal area (%AVAs) in ADPase stained retinas. The NV scores in 0.01 g/ml M-W were significantly lower than those in DW. The %AVAs in 0.05 g/ml DM-A50 and in 0.05 g/ml and 0.01 g/ml M-W were significantly lower than those in DW. There were less catechins, and less caffeine in M-W fraction compared with other GTFs, suggesting components of green tea except for catechins and caffeine might suppress the neovascularization in rat model of OIR

Risk stratification for the prognosis of patients with chemoresistant urothelial cancer treated with pembrolizumab

The use of immune checkpoint inhibitors to treat urothelial carcinoma (UC) is increasing rapidly without clear guidance for validated risk stratification. This multicenter retrospective study collected clinicopathological information on 463 patients, and 11 predefined variables were analyzed to develop a multivariate model predicting overall survival (OS). The model was validated using an independent dataset of 292 patients. Patient characteristics and outcomes were well balanced between the discovery and validation cohorts, which had median OS times of 10.2 and 12.5 mo, respectively. The final validated multivariate model was defined by risk scores based on the hazard ratios (HRs) of independent prognostic factors including performance status, site of metastasis, hemoglobin levels, and the neutrophil-to-lymphocyte ratio. The median OS times (95% confidence intervals [CIs]) for the low-, intermediate-, and high-risk groups (discovery cohort) were not yet reached (NYR) (NYR–19.1), 6.8 mo (5.8-8.9), and 2.3 mo (1.2-2.6), respectively. The HRs (95% CI) for OS in the low- and intermediate-risk groups vs the high-risk group were 0.07 (0.04-0.11) and 0.23 (0.15-0.37), respectively. The objective response rates for in the low-, intermediate-, and high-risk groups were 48.3%, 28.8%, and 10.5%, respectively. These differential outcomes were well reproduced in the validation cohort and in patients who received pembrolizumab after perioperative or first-line chemotherapy (N = 584). In conclusion, the present study developed and validated a simple prognostic model predicting the oncological outcomes of pembrolizumab-treated patients with chemoresistant UC. The model provides useful information for external validation, patient counseling, and clinical trial design

Direct preparation and conversion of copper hydroxide-based monolithic xerogels with hierarchical pores

Accepted 03 Jun 2015Copper hydroxide-based monolithic xerogels with controlled hierarchical pores have been prepared directly by a sol–gel process from an ionic precursor, CuCl[2]·2H[2]O. Propylene oxide acts as a gelation inducer by increasing pH homogeneously in a reaction solution. Poly(acrylamide) is utilized not only to control macroscopic phase separation but also to support the network physically. Glycerol contributes to the formation of monolithic gels by suppressing the growth of copper hydroxide crystals. An appropriate starting composition leads to co-continuous gel skeletons and macropores. Although the as-dried gels were amorphous, post-treatments (calcination and solvothermal treatment) formed metallic copper and copper oxides (CuO and Cu[2]O) without the collapse of the monolithic form and macrostructure

Acute renal failure in a neonate due to bilateral primary obstructive megaureters

A male newborn was referred to our institute for postrenal acute renal failure with bilateral hydroureteronephrosis, electrolyte imbalance, and anuria. Voiding cystourethrography revealed no vesicoureteral reflux or posterior urethral valves. We performed bilateral percutaneous nephrostomy on the 9th post-natal day. The serum creatinine level improved to the normal range. Antegrade pyelography revealed bilateral uretero-vesical junction stenosis. Subsequently, we inserted bilateral double J urethral stents at 1 month. Bilateral ureteroneocystostomy without ureteral folding was performed at 6 months. The postoperative course was uneventful. This is the second case of postrenal acute renal failure with bilateral primary obstructive megaureters in a neonate