Publications by authors named "Ken Sakai"
Objectives: This study aimed to determine interventions and identify risk factors for lymphocele formation following kidney transplant.
Materials And Methods: We conducted a retrospective review of 296 adult kidney transplants from 2010 to 2022 to investigate postoperative lymphocele formation. We divided patients into lymphocele cases and nonlymphocele cases.
The factors controlling the catalytic activity in photochemical hydrogen evolution reaction (HER) are studied in detail for two macrocyclic cobalt compounds bearing two N-heterocyclic carbenes and two pyridyl donors ( and , where has a methoxy substituent on each pyridyl ligand). The present study adopts an aqueous photosystem consisting of EDTA, [Ru(bpy)] (bpy = 2,2'-bipyridine), and MV (MV = methylviologen) at pH = 5. Both catalysts are shown to promote HER in a similar efficiency (TON = 12-13 in 6 h), revealing a minor contribution of the electron-donating methoxy substituents.
View Article and Find Full Text PDFPhotocatalytic reduction of CO to formic acid (HCOOH) was investigated in either organic or aqueous/organic media by employing three water-soluble [RhCp*(LH)Cl] (LH = n,n'-dihydroxy-2,2'-bipyridine; = 4, 5, or 6) in the presence of [Ru(bpy)], 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[]imidazole (BIH) and triethanolamine (TEOA). Through studying the electron-donating effects of two hydroxyl groups introduced into the bipyridyl ligand, we found that the substituent positions greatly affect both the catalytic efficiency and selectivity in CO reduction. More importantly, the HCOOH selectivity shows a dramatic increase from 14 to 83% upon switching the solvent media from pure organic to an aqueous/organic mixture, where the H selectivity shows a reverse phenomenon.
View Article and Find Full Text PDFMembranous nephropathy (MN) recurs in some kidney allograft patients, and recurrence increases graft failure rates. We present a unique case of recurrent MN in first and second allografts showing glomerular capillary wall-positivity for complement receptor 1 (CR1) consistent with immunoglobulin G (IgG). A man in his late 20s developed MN and started hemodialysis.
View Article and Find Full Text PDFArticle Synopsis
- - DMSC (dinuclear metal synergistic catalysis) is a promising method to boost the efficiency of photocatalytic CO reduction, but designing effective dinuclear metal complexes has been challenging due to a lack of understanding of their microenvironment's impact on catalytic activity.
- - A new dinuclear cobalt complex with a planar structure has been developed, demonstrating exceptional catalytic performance for converting CO, achieving turnover numbers (TON) and turnover frequencies (TOF) that are significantly higher than those of a corresponding single-metal complex.
- - The enhanced activity of this dinuclear cobalt complex is attributed to an indirect DMSC effect between the two cobalt ions, facilitating an efficient two-electron transfer process and improved mass transfer, all supported by its unique planar design
Article Synopsis
- The study aimed to investigate the distribution of IgG subclasses in IgG immunofluorescence-positive IgA nephropathy (IgAN) and its clinicopathological significance.
- Out of 27 biopsies from patients, IgG1 was the most frequently positive subclass, showing a negative correlation between biopsy age and IgG1 intensity, while Oxford E and C scores were higher in IgG IF-positive cases.
- The findings suggest that IgG1 plays a prominent role in IgAN, highlighting the need for further research on the implications of IgG subclass staining in understanding the disease's pathogenesis.
We aimed to compare the outcomes of pediatric kidney transplantation (KT) between preemptive KT (PEKT) and non-PEKT in children aged < 6 years. Seventy-four pediatric recipients aged < 6 years who underwent KT were divided into the PEKT and non-PEKT groups. They were retrospectively evaluated for patient and graft survival, graft function, growth, and cytomegalovirus (CMV) infection.
View Article and Find Full Text PDFWater oxidation is a key to achieving sustainable energy cycles, for which higher-valent metal-oxo species often play a key role to accelerate the rate-limiting O-O bond formation. The present study undertook efforts to clarify one of the steps postulated for the water oxidation (WO) catalyzed by [Ru(terpy)(bpy)(OH)] (terpy = 2,2':6',6″-terpyridine, bpy = 2,2'-bipyridine). This study focuses on inner-sphere electron transfer for the Ce-driven oxidation of the Ru═O species into the Ru═O species.
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- A prognostic risk score was created to predict early mortality in elderly Japanese patients starting hemodialysis (HD), emphasizing the importance of this information for patients and their families.
- The study analyzed data from a national registry, identifying nine key risk factors (like age, sex, body mass index, and presence of dementia) that contribute to the prediction of early death within one year of starting HD.
- The developed risk score showed significant correlation with early mortality, helping categorize patients into low, medium, and high-risk groups, which could assist in better decision-making for renal replacement therapy.
The MN ring of Caribbean ciguatoxin C-CTX-1 was synthesized from a --2,7-dimethyloxepane derivative corresponding to the M ring via desymmetrization by acetal formation with a camphor derivative, followed by construction of the N ring via the Horner-Wadsworth-Emmons reaction and acetal formation. The --2,7-dimethyloxepane derivative was synthesized via photoinduced electrocyclization of a conjugated -diene under flow conditions, giving a cyclobutene derivative, followed by ring expansion via oxidative cleavage and diastereoselective reduction of a β-hydroxy ketone.
View Article and Find Full Text PDFPurpose: Patients with chronic kidney disease (CKD) complicated by hypothyroidism exhibit a higher prevalence of urine protein than that in the general population. This study was aimed at investigating thyroid hormones and thyroid hormone-binding proteins excreted in urine to elucidate the urine protein-associated underlying mechanisms of hypothyroidism.
Methods: Between November 2016 and August 2018, thyroid function (serum free T3 [sFT3], free T4 [sFT4], and thyroid-stimulating hormone [sTSH]), kidney function (estimated glomerular filtration rate [eGFR]), thyroid antibodies and albumin (Alb) were evaluated in 99 Japanese CKD patients with proteinuria at our outpatient clinic.
Article Synopsis
- Researchers designed two new Cu(I) photosensitizers with different pyridyl groups to improve CO reduction efficiency through enhanced electron delivery via intermolecular interactions.
- One of the new designs achieved an impressive apparent quantum yield of 76 ± 6% for near-total CO-to-CO conversion, nearly doubling the yield of the original system.
- The study used various advanced spectroscopic techniques to explain how these interactions improve photocatalytic performance, showcasing the potential of optimizing coordination interactions in noble-metal-free systems.
Introduction: In the present study, the efficacy of sotrovimab and molnupiravir in dialysis patients with COVID-19 was investigated using a registry of COVID-19 in Japanese dialysis patients.
Methods: Dialysis patients with confirmed SARS-CoV-2 during the COVID-19 (Omicron BA.1 and BA.
Introduction: This study aimed to determine if immune or nonimmune and acute or chronic lesions associated with mesangiolysis (MGLS) occurred in biopsy-proven pathological chronic active antibody-mediated rejection (P-CAABMR) in kidney transplant biopsies.
Methods: We evaluated MGLS in 41 patients with biopsy findings of P-CAABMR from January 2016 to December 2019. Histological scoring was evaluated by Banff classification.
Article Synopsis
- Arteriovenous fistula (AVF) can occur after a kidney biopsy, often resolving on its own, but in this case, it led to serious complications, including acute kidney injury (AKI) due to urinary tract obstruction.
- A 22-year-old woman, with a history of kidney transplant, was found to have a gourd-shaped AVF that had gone unnoticed for nearly a decade until it caused sudden bleeding and kidney dysfunction.
- The AVF was successfully treated with coil embolization, and although she needed hemodialysis, the function of her kidney gradually improved afterward.*
Introduction: At present, there is limited evidence of the histological impact of vesicoureteral reflux (VUR) on pediatric kidney allografts. In this study, we aimed to investigate the relationship between VUR diagnosed by voiding cystourethrography (VCUG) and 1-year protocol biopsy results.
Methods: One hundred thirty-eight pediatric kidney transplantations were performed in Toho University Omori Medical Center between 2009 and 2019.
A man who was an inactive hepatitis B virus (HBV) carrier with positive hepatitis B surface antigen (HBs antigen) and undetectable HBV-DNA under anti-viral treatment developed nephrotic syndrome at 52 years old, and a renal biopsy revealed advanced membranous nephropathy (MN) with focal cellular crescents, interstitial hemorrhaging, and peritubular capillaritis. Immunofluorescence studies demonstrated granular IgG deposition and HBs antigen-positivity along the capillaries. Glomeruli were negative for phospholipase A2 receptor 1.
View Article and Find Full Text PDFAim: The aim of the present study was to clarify the relationship between the Banff score of the 7-year protocol biopsy and the allograft outcome.
Methods: One-hundred-and-eighty-four patients received kidney transplantation from 2002 to 2008. We excluded patients aged <20 years at transplantation ( = 24), those who did not undergo a 7-year protocol biopsy ( = 66), and those who underwent for-cause biopsy ( = 5).
Few previous studies have reported immune-complex nephropathy that has not been classified as a specific phenotype in kidney allografts. We report a case of a de novo subclinical "full-house" pattern of deposition in a pediatric transplantation recipient with possible donor-derived IgA deposition. A five-year-old boy underwent living kidney transplantation due to congenital kidney and urinary tract anomalies.
View Article and Find Full Text PDFHumoral and cellular responses are critical in understanding immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. Here, we evaluated these responses in hemodialysis (HD) patients after the booster vaccination. SARS-CoV-2 immunoglobulin (IgG) levels, neutralizing antibody titers, and the T-SPOT.
View Article and Find Full Text PDFIntroduction: Multinucleated polyploidization (MNP) of tubular epithelial cells is occasionally observed in kidney allografts. The present study aimed to clarify the clinical and pathological significance of MNP of tubular epithelial cells in kidney allografts.
Methods: Fifty-eight 1-year biopsies from 58 patients who underwent kidney transplantation at our hospital from January 2016 to December 2017 were included.
Natriuretic peptides are associated with malnutrition and volume overload. Over-hydration cannot simply be explained by excess extracellular water in patients undergoing hemodialysis. We assessed the relationship between the extracellular and intracellular water (ECW/ICW) ratio, -terminal pro-B-type natriuretic peptide (NT-proBNP), human atrial natriuretic peptide (hANP), and echocardiographic findings.
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- A study investigated the effects of combining peritoneal dialysis (PD) and hemodialysis (HD) on anemia management in 40 PD patients over 6 months.
- Results showed a significant decrease in the erythropoiesis-stimulating agent (ESA) resistance index (ERI), indicating improved responsiveness to ESA treatment.
- Other clinical improvements included increased hemoglobin and serum albumin levels, as well as reductions in body weight, urinary volume, and serum creatinine.
Article Synopsis
- - A new copper(I) photosensitizer called CuPS, which is water-soluble and has four sulfonate groups, forms a 1:2 complex with hexamethonium cations in water.
- - This combination significantly improves the photophysical and photocatalytic properties of the system.
- - The enhancement is mainly due to reduced energy losses from non-radiative decay when the photosensitizer is excited by light.
Background: The role of fibroblast growth factor 23 (FGF23) levels in mineral metabolism before and after kidney transplantation in pediatric patients is poorly understood.
Methods: We prospectively evaluated 24 patients under 18 years of age (4.5 [3.