Masayuki Tokunaga

Werner's syndrome as "hyaluronuria".

Abstract Although excretion of acid glycosaminoglycans into urine of five patients with Werners syndrome were within normal limits, the quantity of hyaluronic acid increased in this disease. To this novel finding, a term “Hyaluronuria” was proposed.

Hyaluronuria in a Case of Progeria (Hutchinson-Gilford Syndrome)

A classic case of progeria (Hutchinson‐Gilford syndrome) in a 9‐year‐old Japanese boy is presented. The characteristic clinical features in this patient were similar to those reported in the literature. The total amount of acid glycosaminoglycans excreted in the urine was within the normal range, but there was an increase in hyaluronic acid excretion. The hyaluronuria was a novel finding in progeria, providing a common linkage with the hyaluronuria found in Werners syndrome.

Postmortem Study of a Case of Werner's Syndrome

ABSTRACT: The postmortem study of a classic case of Werners syndrome is presented. The subject was a Japanese man who died at the age of 39. Major findings included general microsplanchnia, extreme atrophy of the testes and skin, calcified aortic atherosclerosis, an increase of basophils in the pituitary, aspiration pneumonia, chronic pyelonephritis and a meningioma in the occipital area of the brain. Histologically, no osteoporosis was evident in the lumbar spine and iliac bone. The findings suggest that in Werners syndrome the dominant pathologic factor may be found in connective tissue other than bone.

Fabrication of silica-coated gold nanorods and investigation of their property of photothermal conversion

This study described the preparation of silica-coated Au nanorods (AuNR/SiO2) in a colloidal solution, assessed their property of photothermal conversion, and investigated their ability to kill cancer cells using photothermal conversion. Au-seed nanoparticles were produced by reducing hydrogen tetrachloroaurate (HAuCl4) with sodium borohydride (NaBH4) in aqueous n-hexadecyltrimethylammonium bromide (CTAB) solution. AuNRs were then fabricated by reducing HAuCl4 and silver nitrate (AgNO3) with l-ascorbic acid in the aqueous CTAB solution in the presence of Au-seed nanoparticles. The as-prepared AuNRs were washed by a process composed mainly of centrifugation to remove the CTAB. The washed AuNRs were coated with silica by mixing the AuNR colloidal solution, an aqueous solution of (3-aminopropyl)trimethoxysilane, and tetraethylorthosilicate/ethanol solution with a water/ethanol solution. We found that the addition of AuNR/SiO2 in water, in mice, and in a culture medium with cancer cells, followed by irradiation with a laser, cause an increase in temperature, demonstrating that AuNR/SiO2 have the ability of photothermal conversion. In addition, the cancer cells in the culture medium were found to be killed due to the increase in temperature caused by the photothermal conversion.

Fabrication and dual imaging properties of quantum dot/silica core-shell particles immobilized with gold nanoparticles

ABSTRACT The present work proposes a preparation method for core-shell nanoparticles composed of quantum dots (QDs), SiO2, large Au nanoparticles (AuL), and small Au nanoparticles (AuS). The QDs were silica-coated with a sol-gel method using tetraethyl orthosilicate (QD/SiO2). AuL and AuS were fabricated by reducing Au3+ ions with sodium citrate and tetrakis(hydroxymethyl)phosphonium chloride in water, respectively. Amino groups were introduced onto QD/SiO2 surface by using (3-aminopropyl)-triethoxysilane (QD/SiO2/NH2). Both AuL and AuS were immobilized on QD/SiO2/NH2 by successively reacting AuL and AuS with QD/SiO2/NH2 (QD/SiO2/NH2/AuL/AuS). Surface modification of QD/SiO2/NH2/AuL/AuS was performed by using polyethylene glycol (PEG) with a thiol group (QD/SiO2/NH2/AuL/AuS/PEG). The QD/SiO2/NH2/AuL/AuS/PEG colloid solution could be clearly imaged via its fluorescence. Its computed tomography (CT) value per unit concentration of Au (M) was 1.2 × 104 HU/M. The QD/SiO2/NH2/AuL/AuS/PEGs were circulated in a mouse through blood vessels, and some of them became trapped and accumulated in the liver and spleen. Graphical Abstract

Fabrication of multilayered Au/silica/gadolinium compound core–shell particles and their imaging properties

The present work proposes a preparation method for multilayered Au nanoparticle/silica/gadolinium compound core–shell (Au/SiO2/GdC) particles. Silica-coated Au core–shell (Au/SiO2) particles with a size of 38.0 nm were prepared by a sol-gel reaction in the presence of the Au nanoparticles with a size of 15.5 nm. Multilayered Au/SiO2/GdC particles with sizes of ca. 35–52 nm were prepared by a homogeneous precipitation reaction in the presence of Au/SiO2 particles. The computed tomography (CT) value of the Au/SiO2/GdC colloid solution containing 4.3 × 10−2 M Au was 344.1 HU: Its converted CT value (CT divided by Au concentration) was as large as 8.0 × 103 HU/M. The r1 value of the Au/SiO2/GdC colloid solution was as large as 3.5 mM−1 s−1.