Publications by authors named "Yoshinori Maeda"

Article Synopsis
  • Low oxygen environments, such as 10% O2, better simulate physiological conditions compared to the standard 21% O2 used in most cell cultures for stem cell and cancer research.
  • In neuro-endocrine cells like AtT-20 and pituitaries, lower oxygen levels significantly enhance the storage and secretion of adrenocorticotropic hormone, while the precursor proopiomelanocortin levels remain unchanged.
  • Lower oxygen concentrations also boost the activity of prohormone-processing enzymes, improving the conversion of proinsulin to insulin in pancreatic β-cells, indicating that 10% O2 is optimal for generating active peptide hormones.
View Article and Find Full Text PDF

Secretogranin III (SgIII), a member of the granin family, binds both to another granin, chromogranin A (CgA), and to a cholesterol-rich membrane that is destined for secretory granules (SGs). The knockdown of SgIII in adrenocorticotropic hormone (ACTH)-producing AtT-20 cells largely impairs the regulated secretion of CgA and ACTH. To clarify the physiological roles of SgIII in vivo, we analyzed hormone secretion and SG biogenesis in newly established SgIII-knockout (KO) mice.

View Article and Find Full Text PDF

Photodynamic therapy (PDT) is a promising treatment modality for malignant tumors in a light-selective manner. To improve the PDT efficacy, numerous kinds of nanocarriers have been developed to deliver photosensitizers (PSs) selectively into the tumor through leaky tumor-associated vasculature. However, the corresponding prolonged retention of the nanocarrier in the bloodstream may lead to unfavorable photochemical damage to normal tissues such as skin.

View Article and Find Full Text PDF

Small interfering RNA (siRNA) needs an efficient delivery vehicle to reach the cytoplasm of target cells for successful RNA interference (RNAi) therapy. This study aimed to develop an siRNA-loaded polyion complex (PIC) micelle equipped with a smart polymeric shell featuring tumor targetability and endosome escapability for enhanced RNAi activity in cancer cells. To this end, an acidic pH-responsive polypeptide was designed to exert a stepwise change in its charged state from negative to modestly positive and highly positive in response to slightly acidic environment of tumor (pH ∼6.

View Article and Find Full Text PDF

The expression of secretogranin III (SgIII) in chicken endocrine cells has not been investigated. There is limited data available for the immunohistochemical localization of SgIII in the brain, pituitary, and pancreatic islets of humans and rodents. In the present study, we used immunoblotting to reveal the similarities between the expression patterns of SgIII in the common endocrine glands of chickens and rats.

View Article and Find Full Text PDF

For systemic delivery of siRNA to solid tumors, a size-regulated and reversibly stabilized nanoarchitecture was constructed by using a 20 kDa siRNA-loaded unimer polyion complex (uPIC) and 20 nm gold nanoparticle (AuNP). The uPIC was selectively prepared by charge-matched polyionic complexation of a poly(ethylene glycol)-b-poly(L-lysine) (PEG-PLL) copolymer bearing ∼40 positive charges (and thiol group at the ω-end) with a single siRNA bearing 40 negative charges. The thiol group at the ω-end of PEG-PLL further enabled successful conjugation of the uPICs onto the single AuNP through coordinate bonding, generating a nanoarchitecture (uPIC-AuNP) with a size of 38 nm and a narrow size distribution.

View Article and Find Full Text PDF

For efficient delivery of siRNA into the cytoplasm, a smart block copolymer of poly(ethylene glycol) and charge-conversion polymer (PEG-CCP) is developed by introducing 2-propionic-3-methylmaleic (PMM) amide as an anionic protective group into side chains of an endosome-disrupting cationic polyaspartamide derivative. The PMM amide moiety is highly susceptible to acid hydrolysis, generating the parent cationic polyaspartamide derivative at endosomal acidic pH 5.5 more rapidly than a previously synthesized cis-aconitic (ACO) amide control.

View Article and Find Full Text PDF

Efficient systems for delivery of small interfering RNA (siRNA) are required for clinical application of RNA interference (RNAi) in cancer therapy. Herein, we developed a safe and efficient nanocarrier comprising poly(ethylene glycol)-block-charge-conversional polymer (PEG-CCP)/calcium phosphate (CaP) hybrid micelles for systemic delivery of siRNA and studied their efficacy in spontaneous bioluminescent pancreatic tumors from transgenic mice. PEG-CCP was engineered to provide the siRNA-loaded hybrid micelles with enhanced colloidal stability and biocompatibility due to the PEG capsule and with endosome-disrupting functionality due to the acidic pH-responsive CCP segment where the polyanionic structure could be converted to polycationic structure at acidic pH through cis-aconitic amide cleavage.

View Article and Find Full Text PDF

Perioperative management of a spinocerebellar ataxia patient by epidural anesthesia is reported. A 67-year-old woman with left femur neck fracture underwent femoral head replacement. An epidural catheter was placed without difficulty at the L3-4 interspace using the loss of resistance technique.

View Article and Find Full Text PDF

Background: To prospectively determine the safety and effectiveness of continuous infusion of low-dose remifentanil for the reduction of pain in patients for epidural catheterization.

Methods: This study was approved by the institutional review board. Written informed consent was obtained.

View Article and Find Full Text PDF

Background: Fresh frozen plasma (FFP) should be thawed in a water bath at 30-37 degrees C. Suitable temperature, the prevention for bacterial contamination, and the efficiency of the process are necessary for a thawing procedure. In this study, we compared the clotting factor activity and thawing time in different thawing procedures; a water bath, the thermostatic thawing chamber (FP-40, Hokuyo ; Kawasumi, Japan), and the microwave system (Transfusio-therm 2000 AMCO; Zeipel, Germany).

View Article and Find Full Text PDF

In this study, we describe a multifunctional, nontoxic delivery vehicle with dual-environment sensitivity to deliver plasmid DNA (pDNA) into the cytoplasm of cells. This delivery vehicle was designed to be destabilized by reduction of disulfide cross-links in the intracellular environment and also to contain pH-sensitive membrane-destabilizing activity in acidic late endosomal/lysosomal compartments to allow escape of pDNA into the cell cytoplasm. Polyion complex formation was used to form ternary polyplexes using ionic polymers containing specific chemistries to achieve functional demands.

View Article and Find Full Text PDF

Development of an efficient in vivo delivery vehicle of small interfering RNA (siRNA) is the key challenge for successful siRNA-based therapies. In this study, toward systemic delivery of siRNA to solid tumors, a smart polymer/calcium phosphate (CaP)/siRNA hybrid nanoparticle was prepared to feature biocompatibility, reversible stability and endosomal escape functionality using a pH sensitive block copolymer of poly(ethylene glycol) and charge-conversional polymer (PEG-CCP), of which anionic functional groups could be converted to cationic groups in an endosomal acidic condition for facilitated endosomal escape. Nanoparticles were confirmed to be approximately 100nm in size, narrowly dispersed and spherical.

View Article and Find Full Text PDF

Rapid sphere-to-prism (STP) transformation of silver was studied in aqueous AgNO(3)/NaBH(4)/polyvinylpyrrolidone (PVP)/trisodium citrate (Na(3)CA)/H(2)O(2) solutions by monitoring time-dependent surface plasmon resonance (SPR) bands in the UV-vis region, by examining transmission electron microscopic (TEM) images, and by analyzing emitted gases during fast reaction. Roles of PVP, Na(3)CA, and H(2)O(2) were studied without addition of a reagent, with different timing of each reagent's addition, and with addition of H(2)O(2) to mixtures of spheres and prisms. Results show that prisms can be prepared without addition of PVP, although it is useful to synthesize smaller monodispersed prisms.

View Article and Find Full Text PDF

Background: In surgical graft replacement of the descending aorta graft, one-lung ventilation (OLV) is required to provide adequate surgical view and to allow removal of blood from the left lung. It is best to use a double-lumen tube (DLT) to assure OLV but it is sometimes difficult to place the left-sided DLT due to thoracic aneurysm or the dissection lumen. We retrospectively investigated tracheobronchial anatomy by chest X-ray and chest computed tomography (CT) in 29 cases of descending aorta replacement to determine how best to manage difficult placement of the left-sided DLT.

View Article and Find Full Text PDF

Sivelestat sodium hydrate (sivelestat) is a novel synthetic drug and specific inhibitor of neutrophil elastase that has been approved in Japan as a treatment for acute lung injury associated with systemic inflammatory response syndrome. It is important to determine how sivelestat affects hemodynamics and the regulatory mechanisms of vascular smooth muscle (VSM). We recently found that sivelestat relaxes porcine coronary artery VSM via selective inhibition of Ca(2+) sensitization induced by a receptor agonist without affecting the normal Ca(2+)-induced contraction.

View Article and Find Full Text PDF

Sivelestat sodium hydrate (sivelestat) is a novel synthetic drug and specific inhibitor of neutrophil elastase that has been approved in Japan as a treatment for acute lung injury associated with systemic inflammatory response syndrome. There are no reports on the effects of sivelestat on the contractile regulation of vascular smooth muscle. The purpose of the present study was to assess the effects of sivelestat on porcine coronary artery.

View Article and Find Full Text PDF

A 35-year-old female with malabsorption syndrome who underwent a pancreatoduodenectomy for multiple endocrine adenomatosis 13 years prior was admitted to our hospital with diarrhea, general fatigue, high fever, and eruption in the lower legs. The patient had consumed raw shrimp a few days before onset and presented systemic inflammatory response syndrome at the time of hospitalization. Vibrio vulnificus was isolated from a blood culture performed before admission to the intensive care unit.

View Article and Find Full Text PDF

A 54-year-old man with severe emphysema and stenosis of coronary artery was scheduled for combined surgery of lung volume reduction and an off-pump coronary artery bypass grafting. His FEV1.0 was 600 ml and %FEV1.

View Article and Find Full Text PDF