Publications by authors named "Koyo Nishida"

Article Synopsis
  • The nucleic acids dilution-induced assembly (NADIA) method is a new approach to prepare lipid nanoparticles by using an alcohol phase, avoiding the precipitation found in traditional methods.
  • By mixing propylene glycol with sodium chloride, researchers successfully dispersed plasmid DNA and protamine sulfate in this alcohol phase, leading to the development of extracellular vesicle-mimicking lipid nanoparticles (ELNPs).
  • The use of a microfluidic device resulted in improved consistency in particle size, polydispersity, and transfection efficiency in HepG2 cells, offering a scalable solution for pharmaceutical applications of complex formulations like these lipid nanoparticles.
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Typical examples of non-viral vectors are binary complexes of plasmid DNA with cationic polymers such as polyethyleneimine (PEI). However, problems such as cytotoxicity and hemagglutination, owing to their positively charged surfaces, hinder their in vivo use. Coating binary complexes with anionic polymers, such as γ-polyglutamic acid (γ-PGA), can prevent cytotoxicity and hemagglutination.

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This study aimed to develop a new and effective application form for the liver surface. We designed a two-layered sheet for the controlled release and local disposition of the anticancer drug, 5-fluorouracil (5-FU), without leakage into the peritoneal cavity. We employed poly(lactic-co-glycolic acid) (PLGA) and hydroxypropyl cellulose (HPC) to form two-layered sheets by attaching a cover sheet and a drug-containing sheet.

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Cationic lipid-based lipoplexes are well-known for gene delivery. To determine the relationship between physicochemical characteristics and transfection efficiency, cationic liposomes of different sizes were prepared and incubated with plasmid DNA at different temperatures to form lipoplexes. We found that the liposome diffusion coefficient during lipoplex formation strongly correlated with the physicochemical characteristics of lipoplexes, accessibility of plasmid DNA in lipoplexes, and logarithm of gene expression per metabolic activity.

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The generation of reactive oxygen species (ROS) can affect cationic liposome-mediated transfection. In this study, we focused on a specific class of antioxidants, flavonoids, to investigate the transfection efficiency using cationic liposome/plasmid DNA complexes (lipoplexes) in 2D and 3D cultures of Colon26 and HepG2 cells, respectively. All tested flavonoids enhanced the transfection efficiency in 2D Colon26 and HepG2 cells.

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Here, I report recent advances in lipid-based drug delivery systems, with a focus on their production, controlled drug release, targeting, and co-delivery [...

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We developed a biocompatible splenic vector for a DNA vaccine against melanoma. The splenic vector is a ternary complex composed of plasmid DNA (pDNA), biodegradable dendrigraft poly-L-lysine (DGL), and γ-polyglutamic acid (γ-PGA), the selective uptake of which by the spleen has already been demonstrated. The ternary complex containing pDNA encoding luciferase (pCMV-Luc) exhibited stronger luciferase activity for RAW264.

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Nucleic acid and genetic medicines are increasingly being developed, owing to their potential to treat a variety of intractable diseases. A comprehensive understanding of the in vivo fate of these agents is vital for the rational design, discovery, and fast and straightforward development of the drugs. In case of intravascular administration of nucleic acids and genetic medicines, interaction with blood components, especially plasma proteins, is unavoidable.

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Visualizing biological events and states to resolve biological questions is challenging. Tissue clearing permits three-dimensional multicolor imaging. Here, we describe a pH-adjustable tissue clearing solution, Seebest (SEE Biological Events and States in Tissues), which preserves lipid ultrastructures at an electron microscopy level.

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The pharmacokinetics of some hepatically cleared drugs have been reported to fluctuate in patients with renal impairment, but the definitive factors have not been clarified. We compared the pharmacokinetics of some drugs with different hepatic elimination processes in a chronic kidney disease (CKD) rat model, to optimize their administration during kidney injury. We chose indocyanine green (ICG), midazolam (MDZ), and acetaminophen (APAP) as reference drugs to determine changes in hepatic clearance pathways in presence of CKD.

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Cancer treatments have improved significantly during the last decade but are not yet satisfactory. Combination therapy is often administered to improve efficacy and safety. Drug delivery systems can also improve efficacy and safety.

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Understanding the in vivo fate of lipoplex, which is composed of cationic liposomes and DNA, is an important issue toward gene therapy. In disease conditions, the fate of lipoplex might change compared with the normal condition. Here, we examined the contribution of interaction with serum components to in vivo transfection using lipoplex in hepatitis mice.

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We previously developed a renal pressure-mediated transfection method (renal pressure method) as a kidney-specific in vivo gene delivery system. However, additional information on selecting other injection routes and applicable animals remains unclear. In this study, we selected renal arterial and ureteral injections as local administration routes and evaluated the characteristics of gene delivery such as efficacy, safety, and distribution in pressured kidney of rat.

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We examined the influence of liver disease on the absorption from the liver surface of fluorescein isothiocyanate (FITC)-dextran 10 (FD-10, MW: 11000) and several marker compounds with different molecular weights. The purpose of this study was to determine the feasibility of liver surface application of macromolecular compounds in the disease state. We used male Wistar rats treated with carbon tetrachloride (CCl) or D-galactosamine (GAL).

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Vescalagin () is a major ellagitannin from young spring leaves of ; however, the amount of decreases as the leaves mature with a concomitant rise in the levels of catechin () and procyanidins. In this report, the chemical mechanism responsible for the degradation of was investigated. In vitro model experiments indicated that initially a polyphenol oxidase oxidizes the catechin B-ring, and the resulting catechin -quinone oxidizes one of the pyrogallol rings of to give a cyclopenten-1,2-dione-type product .

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Article Synopsis
  • A new method was created to track transgene expression in tissues by sampling blood, using plasmid DNA (pDNA) with firefly luciferase as a reporter gene and a secretable luciferase as a monitor gene in mice.* -
  • The study found strong correlations between the levels of the reporter and monitor genes in the treated muscle and their levels in the plasma, regardless of the method used to administer the pDNA.* -
  • This technique was named 'Therapeutic transgene monitoring (TTM)', drawing parallels to the established concept of 'Therapeutic drug monitoring (TDM)'.*
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The leaves of (Fagaceae) contain characteristic hexahydroxydiphenoyl (HHDP) esters of 28--glucosyl 2α,3β,23,24-tetrahydroxyolean- and urs-12-en-28-oic acids. In this study, uncharacterized substances were detected in the young leaves, which are not observed in the mature leaves. Preliminary HPLC analyses indicated that the substances had dehydro-HHDP (DHHDP) ester groups; however, the esters were unstable and decomposed during extraction.

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1. The expression and activity of drug-metabolizing enzymes are known to affect the pharmacokinetics of drugs metabolized in the liver. Here, we assessed the effect of acetaminophen (APAP)-induced hepatotoxicity on the mRNA expression of drug-metabolizing enzymes and elucidated the underlying mechanism using three-dimensional (3D) cultures of HepG2 cells.

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Objectives: This study aimed to investigate the effects of renal ischaemia/reperfusion (I/R)-induced acute kidney injury (AKI) on the distribution of midazolam (MDZ), a probe drug for cytochrome P450 3A (CYP3A) activity.

Methods: We established an AKI model inducing ischaemia of both renal pedicles for 60 min followed by 24-h reperfusion. MDZ was administered intravenously (i.

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In the present study, we developed a sonoporation system, namely "direct sonoporation", for transfecting the peritoneum from a defined surface area to avoid systematic side effects. Here, the transfection characteristics are explained because there is less information about direct sonoporation. Naked pDNA and nanobubbles were administered to diffusion cell attached to the visceral and parietal peritoneum from the liver and peritoneal wall surface, respectively.

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Synchronized bio-distribution of combination therapies has several merits such as synergistic effects and reduced side-effects. Co-delivery of a protein and small molecule drug using a single nanocarrier is challenging because they possess totally different characteristics. Herein, we report the development of sophisticated nanoparticles composed of lipids, calcium carbonate and RGD peptide ligands for the co-delivery of a protein and small molecule drug combination via a simple preparation method.

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Four new ellagitannin metabolites, penthorumnins A-D (1-3 and 5), were isolated from the dried stem of Penthorum chinense. The structures were determined using spectroscopic and chemical analysis as well as using computations that revealed the following: (1) the acyl group of penthorumnin A (1) has a unique cyclopentane carboxylic acid structure that is derived from a hexahydroxydiphenoyl (HHDP) group; (2) penthorumnin B (2) has a 2-carboxymethyl-2,3-dihydro-3-oxo-1 H-indene-1-carboxylic acid structure that originates from the acyl group of penthorumnin A; (3) penthorumnin C (3) is a glucoside of trihydroxyacetophenone with an acyl group that is oxidatively derived from the HHDP group. This acyl group is closely related to that of balanophotannin F (4), which has been previously isolated from Balanophora japonica and whose absolute configuration has been revised using the DFT method; and (4) penthorumnin D (5) is defined as 2',4',6'-trihydroxyacetophenone 4'- O-[4,6-( S)-dehydrohexahydroxydiphenoyl]-β-glucoside.

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A requirement of gene therapy is efficient nucleic acid delivery. However, the application of cationic liposomes to gene therapy is restricted by their inefficient transfection capacity, which may be caused by cytotoxicity. This cytotoxicity is highly dependent on cationic lipid-induced reactive oxygen species (ROS).

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In the delivery of cell-impermeable molecules, cell-penetrating peptides (CPPs) have been attracting increasing attention as intracellular delivery tools. In the present study, we designed four types of cyclic α,α-disubstituted α-amino acids (dAAs) with basic functional groups on their five-membered rings and different chiralities at the α-position and introduced them into arginine (Arg)-rich peptides. The evaluation of cell-penetrating abilities indicated that these peptides exhibited better cell permeabilities than an Arg nonapeptide.

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