Biomedical subjects

Tsuyoshi Okazaki

Publications and source records attributed to Tsuyoshi Okazaki.

4 recordsLinked to original sources

PubMed2005

Cholesterol-armed cyclens for helical metal complexes offering chiral self-aggregation and sensing of amino acid anions in aqueous solutions.

Cholesterol-armed cyclens worked as octadentate receptors for Na+, Ca2+, and Y3+ complexes in which four chiral cholesterol-functionalized sidearms were bundled and asymmetrically twisted above cyclen-metal complex platforms. Since the resulting helical metal complexes included chiral, hydrophobic cholesterol residues and charged, hydrophilic metal sites as well as asymmetric coordination geometries, they exhibited unique amphiphilic properties and provided chiral self-aggregates in aqueous solutions. Light scattering, fluorescence, and TEM characterizations demonstrated that Na+ complex with cholesterol-armed cyclen gave a particularly stable self-aggregate in aqueous solution and offered supramolecular environments effective for sensing and detection of amino acid anions. Various dansylamino acid derivatives (dansyl = 5-(dimethylamino)-1-naphthalenesulfonyl) were nicely accommodated in the helicate aggregates to give highly enhanced fluorescence signals, which could be detected by the naked eye at 10(-7) mol/L level. Their inclusion behaviors were analyzed by a Langmuir-type equation, indicating that enantiomer-selective inclusion occurred. MM/MD calculations and circular dichroism (CD) studies further suggested that cholesterol-armed cyclen helicates have chiral and hydrophobic cavities upon self-aggregation, in which the dansylamino acid anions were specifically accommodated. Since these helicates exhibited nonselective binding abilities in solvent extraction experiments of dansylamino acid anions, uncommon chiral recognition and sensing functions were generated by supramolecular alignments of the chiral metal helicates in the aqueous solutions.

Amino Acids↗

PubMed2004

Synovial sarcoma of the mediastinum: report of a case.

We report a case of synovial sarcoma of the mediastinum, a very rare tumor, in a 50-year-old man hospitalized with anterior chest pain. Chest X-ray and computed tomography (CT) on admission showed a 10 x 8-cm mass in the right anterior mediastinal space, compressing the superior vena cava. A diagnosis of sarcoma was established by a CT-guided percutaneous needle biopsy. Systemic examination revealed no metastasis to the contralateral pleural cavity or other distant organs, and we resected the mediastinal sarcoma. Pathological and immunohistochemical analyses confirmed a diagnosis of monophasic synovial sarcoma. The patient is alive with recurrence 9 months after his operation, and is receiving chemotherapy with ifosfamide.

Humans↗

PubMed2003

Operation for lung cancer in patients with idiopathic pulmonary fibrosis: surgical contraindication?

BACKGROUND: Patients with idiopathic pulmonary fibrosis have an increased incidence of lung cancer. The purpose of this study was to determine the outcome of surgical treatment of lung cancer with idiopathic pulmonary fibrosis. METHODS: From January 1992 through December 2001, 64 patients who had simultaneous lung cancer and idiopathic pulmonary fibrosis were treated. Twenty-one (33%) of them underwent surgical resection of lung cancer, and their data were reviewed. RESULTS: There were 56 men and 8 women with an average age of 69 years (range, 43 to 85 years). In the surgical group, there were no early postoperative deaths, and nonfatal complications occurred in 2 patients (10%). Among the 14 patients with stage I cancer, a second primary lung cancer developed in 5 (36%). The causes of death in the surgical group were cancer related in 7 patients, exacerbation of idiopathic pulmonary fibrosis in 7, and other in 2. Five of the 7 patients who died of a cancer-related cause had development of a second primary lung cancer. The actuarial 2-year survival rate of the surgical group was 52% overall, 58% for patients with N0 or N1 disease and 25% for those with N2 disease (p = 0.05). CONCLUSIONS: The long-term results in one surgical group were poor partly because of the high incidence of a second primary lung cancer and partly because of the poor natural history of idiopathic pulmonary fibrosis. These patients require intensive surveillance even after curative resection of lung cancer.

Adult↗

PubMed1999

Side Arm Effects on Cyclen-Alkali Metal Cation Complexation: Highly Selective and Three-Dimensional Encapsulation of Na(+) Ion.

A variety of armed cyclens were prepared in which ester, amide, nitrile, and pyridine moieties were attached as cation-ligating side arms to a 12-membered ring. Ester-, amide-, and pyridine-armed cyclens nicely accommodated a Na(+) ion in a three-dimensional fashion and clearly discriminated the cation from Li(+) and K(+) ions. They extracted Na(+) ion more efficiently and selectively than common Na(+) ion-selective ligands. X-ray diffraction, FAB-MS, (23)Na NMR binding studies, and computer modeling experiments demonstrated that the cyclens having ester-, amide-, and pyridine-functionalized side arms formed highly selective encapsulated Na(+) complexes via a cooperative action of parent cyclen and side arms.

Journal Article↗