Publications by authors named "Kazuya Nagata"

Marine diatoms are responsible for up to 20% of the annual global primary production by performing photosynthesis in seawater where CO2 availability is limited while HCO3- is abundant. Our previous studies have demonstrated that solute carrier 4 proteins at the plasma membrane of the diatom Phaeodactylum tricornutum facilitate the use of the abundant seawater HCO3-. There has been an unconcluded debate as to whether such HCO3- use capacity may itself supply enough dissolved inorganic carbon (DIC) to saturate the enzyme Rubisco.

View Article and Find Full Text PDF

The incidence of inflammatory bowel disease (IBD) is increasing. Nucleic acid-based medicine has potential as a next-generation treatment, but it is rarely successful with IBD. The aim of this study was to establish a microRNA-based therapy in an IBD model.

View Article and Find Full Text PDF

Considerable attention has been paid to protein tyrosine phosphatase 1B (PTP1B) inhibitors as a potential therapy for diabetes, obesity, and cancer. Ten caffeoylquinic acid derivatives (1-10) from leaves of Artemisia princeps Pamp. (Asteraceae) were identified as natural PTP1B inhibitors.

View Article and Find Full Text PDF

Aim: Alzheimer's disease causes loss of appetite, resulting in bodyweight reduction. This, in turn, causes progression of cognitive dysfunction and physical complications that hasten death. Earlier care for loss of appetite is essential in Alzheimer's disease management.

View Article and Find Full Text PDF

The rhizomes of Polygonatum odoratum represent a traditional Chinese medicine and functional food. A phytochemical investigation resulted in the isolation of eight steroidal glycosides (1-8), including two new compounds, polygonatumosides F (1) and G (2). The structures were elucidated by spectroscopic data and chemical reactions.

View Article and Find Full Text PDF

Recent studies have shown that microRNAs (miRNAs) are involved in the progression of colorectal cancer (CRC). The aim of this study is to identify a novel miRNA that especially relates to liver metastasis and to explore the underlying mechanism. Differentially expressed miRNAs were analyzed using microarray, in primary CRC tumors without metastasis (n=16), those with liver metastasis (n=12), and liver metastatic lesions (n=8).

View Article and Find Full Text PDF

Selectively spooling single plasmid DNA (pDNA), as a giant polyelectrolyte, into a nanosized toroidal structure or folding it into a rod-like structure has been accomplished by polyion complexation with block catiomers to form polymeric micelles in varying NaCl concentrations. The interactive potency between the pDNA and block catiomers was determined to play a critical role in defining the ultimate structure of the pDNA; the formation of toroidal or rod-like structures was achieved by complexation in 600 or 0 mM NaCl solutions, respectively. Compared with the rod-like structure, the toroidal structure possessed superior biological functions capable not only of elevating in vitro transcription but also of elevating in vivo gene transduction efficiency.

View Article and Find Full Text PDF

The recovery of neurologic function after peripheral nerve injury often remains incomplete because of the prolonged reinnervation process, which leads to skeletal muscle atrophy and articular contracture from disuse over time. To rescue the skeletal muscle and promote functional recovery, insulin-like growth factor-1 (IGF-1), a potent myogenic factor, was introduced into the muscle by hydrodynamic injection of IGF-1-expressing plasmid DNA using a biocompatible nonviral gene carrier, a polyplex nanomicelle. In a mouse model of sciatic nerve injury, the introduction of IGF-1 into the skeletal muscle of the paralyzed limb effectively alleviated a decrease in muscle weight compared with that in untreated control mice.

View Article and Find Full Text PDF

Excitotoxicity describes a pathogenic process whereby death of neurons releases large amounts of the excitatory neurotransmitter glutamate, which then proceeds to activate a set of glutamatergic receptors on neighboring neurons (glutamate, N-methyl-D-aspartate (NMDA), and kainate), opening ion channels leading to an influx of calcium ions producing mitochondrial dysfunction and cell death. Excitotoxicity contributes to brain damage after stroke, traumatic brain injury, and neurodegenerative diseases, and is also involved in spinal cord injury. We tested whether low level laser (light) therapy (LLLT) at 810 nm could protect primary murine cultured cortical neurons against excitotoxicity in vitro produced by addition of glutamate, NMDA or kainate.

View Article and Find Full Text PDF

Low-level laser (light) therapy (LLLT) involves absorption of photons being in the mitochondria of cells leading to improvement in electron transport, increased mitochondrial membrane potential (MMP), and greater ATP production. Low levels of reactive oxygen species (ROS) are produced by LLLT in normal cells that are beneficial. We exposed primary cultured murine cortical neurons to oxidative stressors: hydrogen peroxide, cobalt chloride and rotenone in the presence or absence of LLLT (3 J/cm², CW, 810 nm wavelength laser, 20 mW/cm²).

View Article and Find Full Text PDF

Spontaneous formation of polymeric metallosomes with uniform size (~100 nm) was found to occur in aqueous medium through the reaction of an anticancer agent, (1,2-diaminocyclohexane)platinum(II) (DACHPt), with a Y-shaped block copolymer of ω-cholesteroyl-poly(L-glutamic acid) and two-armed poly(ethylene glycol) (PEGasus-PLGA-Chole). Circular dichroism spectrum measurements revealed that the PLGA segment forms an α-helix structure within the metallosomes, suggesting that secondary-structure formation of metallocomplexed PLGA segment may drive the self-assembly of the system into vesicular structure. These metallosomes can encapsulate water-soluble fluorescent macromolecules into their inner aqueous phase and eventually deliver them selectively into tumor tissues in mice, owing to the prolonged blood circulation.

View Article and Find Full Text PDF

Ultra-early surgical treatment in which associated brain injury is minimized and maximal volume of hematoma is removed shortly after onset with secure hemostasis is expected to be established. We developed a transparent guiding sheath and other surgical instruments for endoscopic surgery and established a novel, ultra-early stage surgical procedure using those instruments. This procedure has the following characteristics: (a) burr hole opening under local anesthesia is possible; (b) a transparent sheath improves the visualization of the surgical field in the parenchyma and the hematoma; (c) free-hand surgery without fixing an endoscope and a sheath to a frame facilitates three-dimensional operation; (d) secure hemostasis by electric coagulation is possible; (e) relatively simple surgical instruments are easy to prepare.

View Article and Find Full Text PDF

Background And Purpose: Inertial force of the bloodstream results in the local elevation of intravascular pressure secondary to flow impact. Previous studies suggest that this "impacting force" and the local pressure elevation at the aneurysm may have a large contribution to the development of cerebral aneurysms. The goal of the present study is to evaluate how the bloodstream impacting force and the local pressure elevation at the aneurysm influences the rupture of cerebral aneurysms.

View Article and Find Full Text PDF

Object: The head-shaking method combined with cisternal irrigation has been proposed to be effective in preventing cerebral vasospasm after subarachnoid hemorrhage (SAH) by facilitating rapid washout of the clot from the subarachnoid space. This study was conducted to evaluate the effectiveness of this method.

Methods: The inclusion criteria included the following: 1) Fisher Grade 3 SAH on admission computerized tomography (CT) scans; 2) aneurysm secured within 48 hours of SAH onset; and 3) no focal deficit and ability to obey commands within 24 hours postsurgery.

View Article and Find Full Text PDF

We have characterised the blood vessels found in normal cerebral vasculature and in arteriovenous malformations (AVMs), based on the expression of smooth muscle cell (SMC)-specific proteins. The marker proteins used were smooth muscle alpha-actin and four myosin heavy chain isoforms (SM1, SM2, SMemb and NMHC-A). Specimens of AVM obtained during surgery, and normal cerebral vessels from autopsy cases were studied immunohistochemically and compared.

View Article and Find Full Text PDF

Oxidative degradation of ultra-high molecular weight polyethylene (UHMWPE) attributed to sterilization by gamma-radiation in the presence of air has been cited as one of the major causes of premature wear in total joint arthroplasty. For example, in retrieved UHMWPE tibial bearings, not only adhesive and abrasive wear, but also fatigue wear characterized by delamination and fracture is frequently observed. In this study, we examined the effects of gamma radiation on the microstructural morphology of UHMWPE tibial bearings, and propose a severe fatigue wear mechanism.

View Article and Find Full Text PDF

We report a case of a bilateral vertebral dissecting aneurysm associated with subarachnoid hemorrhage. Proximal ligation of the vertebral artery on the ruptured side combined with wrapping of the contralateral dissection failed to prevent fatal rebleeding. Since enlargement of the contralateral dissection was observed by postoperative angiography, rupture of the growing contralateral dissecting aneurysm may have caused rebleeding.

View Article and Find Full Text PDF