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271 results on '"Gonda, K."'

9. Fabrication of gold-immobilized quantum dots/silica core–shell nanoparticles and their multimodal imaging properties.

Author

Tayama, M., Inose, T., Yamauchi, N., Nakashima, K., Tokunaga, M., Kato, C., Gonda, K., and Kobayashi, Y.

Subjects
NANOFLUIDS, QUANTUM dots, X-ray fluorescence, GOLD nanoparticles, SILICA nanoparticles, X-ray imaging
Abstract

This work describes the fabrication of quantum dot (QD)/silica (SiO2) core–shell particles immobilized with Au nanoparticles and the evaluation of their abilities in fluorescence and x-ray computed tomography (CT) imaging. The QD nanoparticles were coated with silica shells by a sol-gel method using tetraethyl orthosilicate (QD/SiO2). Reduction of Au3+ in a citrate aqueous solution gave an Au nanoparticle colloidal solution. (3-Mercaptopropyl)trimethoxysilane thiolated the QD/SiO2 particle surface (QD/SiO2/SH). Immobilization of the Au nanoparticles on the QD/SiO2/SH particle surface was performed with the addition of the Au nanoparticle colloidal solution to the QD/SiO2/SH nanoparticle colloidal solution (QD/SiO2/SH/Au). Surface-PEGylated QD/SiO2/SH/Au particles were fabricated using thiol-terminated polyethylene glycol (PEG) (QD/SiO2/SH/Au/PEG). The QD/SiO2/SH/Au/PEG nanoparticle colloidal solution was imaged by fluorescence and x-ray CT imaging techniques. The CT value per unit concentration of Au (M) for the QD/SiO2/SH/Au/PEG nanoparticle colloidal solution was 1.5 × 104 HU/M. The QD/SiO2/SH/Au/PEG nanoparticle colloidal solution was injected into the tail vein of a mouse and circulated in the blood, although some QD/SiO2/SH/Au/PEG nanoparticles were trapped and remained in the liver and spleen. [ABSTRACT FROM AUTHOR]

Published
2022
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10. Alternating current magnetic susceptibility and heat dissipation by Mn1-xZnxFe2O4 nanoparticles for hyperthermia treatment.

Author

Kondo, T., Mori, K., Hachisu, M., Yamazaki, T., Okamoto, D., Watanabe, M., Gonda, K., Tada, H., Hamada, Y., Takano, M., Ohuchi, N., and Ichiyanagi, Y.

Subjects
MAGNETIC susceptibility, HEAT losses, THERMAL expansion, ELECTROMAGNETIC waves, MAGNETIC properties
Abstract

Mn-Zn ferrite, Mn1-xZnxFe2O4 nanoparticles encapsulated in amorphous SiO2 were prepared using our original wet chemical method. X-ray diffraction patterns confirmed that the diameters of these particles were within 7-30 nm. Magnetization measurements for various sample compositions revealed that the saturation magnetization (Ms) of 7 nm particles was maximum for the x=0.2 sample. AC magnetic susceptibility measurements were performed for Mn0.8Zn0.2Fe2O4 (x=0.2) samples with 13-30 nm particles. The peak of the imaginary part of the magnetic susceptibility Xn shifted to higher temperatures as the particle size increased. An AC field was found to cause the increase in temperature, with the 18 nm particles exhibiting the highest temperature increase, as expected. In addition, in vitro experiments were carried out to study the hyperthermia effects of Mn1-xZnxFe2O4 (x=0.2, 18 nm) particles on human cancer cells. [ABSTRACT FROM AUTHOR]

Published
2015
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13. Potential curing and beneficial effects of Ooitabi (Ficus pumila L.) on hypertension and dyslipidaemia in Okinawa.

Author

Suzuki, K., Gonda, K., Kishimoto, Y., Katsumoto, Y., and Takenoshita, S.

Subjects
*PHYTOTHERAPY, *DRUG therapy for hyperlipidemia, *THERAPEUTIC use of tea, *HYPERTENSION, *BLOOD pressure, *LOW density lipoproteins, *PROTEOLYTIC enzymes, *BODY mass index, *URIC acid, *CHOLESTEROL, THERAPEUTIC use of plant extracts
Abstract

Background: Over 30% of the population of Okinawa Prefecture have a high body mass index. The incidence of hypertension and dyslipidaemia has also increased in recent years. We found that Ooitabi (Ficus pumila L.), a plant native to Okinawa, was useful for hypertension. During ancient times, the extracts of Ooitabi leaves were used for making Ishimaki tea in some areas of Okinawa Prefecture. The plants in Okinawa are rich in antioxidants, and four flavonoid glycosides, including rutin, have been identified in Ooitabi. Methods: In the present study, we conducted clinical verification tests on the effects of drinking Ishimaki tea on outpatients with hypertension and dyslipidaemia. Of 3814 Japanese patients who underwent medical check‐ups in Okinawa, 38 individuals with high blood pressure, dyslipidaemia, liver dysfunction and gout visited our hospital as outpatients and were asked to drink Ishimaki tea. Results: After 3 months, there were significant reductions in body mass index, systolic and diastolic blood pressure, total cholesterol, low‐density lipoprotein cholesterol, γ‐glutamyltrans peptidase, uric acid and ratio of blood vessel insulin resistance. Conclusions: Ooitabi extract can lower blood pressure and improve lipid abnormalities and has likely contributed to the well‐known health and longevity of the population in Okinawa. [ABSTRACT FROM AUTHOR]

Published
2021
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15. Abstract P2-09-28: New quantitative diagnostic method by fluorescence nanoparticle for HER2 positive breast cancer treated with neoadjuvant lapatinib and trastuzumab: The Neo LaTH study (JBCRG-16TR)

Author

Tada, H, primary, Miyashita, M, additional, Gonda, K, additional, Watanabe, M, additional, Suzuki, A, additional, Watanabe, G, additional, Harada, N, additional, Sato, A, additional, Hamanaka, Y, additional, Masuda, N, additional, Toi, M, additional, Ohno, S, additional, Bando, H, additional, Ishiguro, H, additional, Inoue, K, additional, Yamamoto, N, additional, Kuroi, K, additional, Ohuchi, N, additional, and Ishida, T, additional

Published
2018
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36. Heterotopic Ossification of Degenerating Rat Skeletal Muscle Induced by Adenovirus‐Mediated Transfer of Bone Morphogenetic Protein‐2 Gene*

Author

Dr. Gonda, K., Nakaoka, T., Yoshimura, K., Otawara‐Hamamoto, Y., and Harrii, K.

Abstract

In vivo gene transfer is a recently developed device for efficient delivery of a therapeutic recombinant protein. We formulated the hypothesis that a high level of expression of bone morphogenetic protein 2 (BMP‐2) could be a future therapeutic modality in terms of inducing substantial bone formation in vivo. First, to test this hypothesis, adenoviruses carrying BMP‐2gene were directly injected into the soleus muscle of adult rat. The BMP‐2gene was successfully overexpressed in the target muscle by adenovirus‐mediated transfer, whereas bone formation in and around the muscle failed to occur in this case. Second, to recruit putative osteoprogenitor cells, we then induced ischemic degeneration of the target muscle by orthotopically grafting it simultaneously with the gene transfer. The combination of BMP‐2gene transfer and orthotopic muscle grafting resulted in successful ossification of almost the whole grafted muscle, whereas neither muscle grafting alone nor the combination of muscle grafting and adenovirus‐mediated transfer of reporter gene LacZinduced any bone formation in the muscle. The ossification process was evident by positive von Kossa staining of the histological sections and roentgenographical radio‐opacity of the region. It was also found that the BMP‐2transgene overexpressed in grafted muscles inhibited muscle regeneration, which should otherwise follow the muscle degeneration. We further demonstrated an up‐regulation of BMP receptor type IA in grafted muscles, suggesting its involvement in the bone‐formation process. In conclusion, overexpression of BMP‐2gene induced massive heterotopic ossification in skeletal muscles under graft‐induced ischemic degeneration, which possibly up‐regulates osteoprogenitor cells in situ.

Published
2000
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37. EDG1 is a functional sphingosine-1-phosphate receptor that is linked via a Gi/o to multiple signaling pathways, including phospholipase C activation, Ca2+ mobilization, Ras-mitogen-activated protein kinase activation, and adenylate cyclase inhibition.

Author

Okamoto, H, Takuwa, N, Gonda, K, Okazaki, H, Chang, K, Yatomi, Y, Shigematsu, H, and Takuwa, Y

Abstract

In Chinese hamster ovary (CHO) cells transiently transfected with an expression vector for EDG1, but not an empty vector, sphingosine-1-phosphate (SP) at a concentration as low as 10(-10) M caused an increase in the intracellular free Ca2+ concentration ([Ca2+]i) as a result of mobilization of Ca2+ from both intracellular and extracellular pools. In a CHO clone stably expressing EDG1 receptor (CHO-EDG1 cells), SP induced increases in the production of inositol phosphates and the [Ca2+]i and inhibited forskolin-induced increase in the cellular cAMP content, all in a manner sensitive to pertussis toxin. SP also activated mitogen-activated protein kinase in CHO-EDG1 cells in pertussis toxin-sensitive and Ras-dependent manners. To evaluate the spectrum of agonists for EDG1, we used human erythroleukemia (HEL) cells, which at naive state do not respond to SP or structurally related lipids with an increase in the [Ca2+]i. In HEL cells stably expressing EDG1 receptor (HEL-EDG1 cells), SP dose-dependently increased the [Ca2+]i with half-maximal and maximal concentration values of 10(-9) and 3 x 10(-7) M, respectively; sphingosylphosphorylcholine at exclusively high concentrations, but not sphingosine at all, also increased the [Ca2+]i. HEL-EDG1 cells bound 32P-labeled SP, which was displaced dose dependently by unlabeled SP. These results indicate that EDG1, a member of the EDG family G protein-coupled receptors, is a specific, high-affinity SP receptor.

Published
1998

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