Biomedical subjects

Satoshi Ozawa

Publications and source records attributed to Satoshi Ozawa.

4 recordsLinked to original sources

PubMed2006

Ultra-slim laminated capillary array for high-speed DNA separation.

We developed a new kind of capillary array for electrophoresis by using the numerical-control (NC) wiring technique conventionally used to produce printed-circuit boards. Laminating two polyimide sheets after laying cylindrical capillaries between them according to designed geometries, we fabricated a 16-lane laminated capillary array (LCA) 9.9 cm long, 7.2 cm wide, and 0.5 mm thick in which the effective length of all capillaries was only 10.9 cm. This compact LCA thus had separation columns as short as those in capillary array electrophoresis chips fabricated by lithography techniques. Like conventional capillary arrays, it also enabled pipetting-less direct injection of analytes from sample preparation plates. Using the LCA with LIF detection and a replaceable fluid sieving matrix, we demonstrated high-speed ssDNA fragment separations. At an electric field strength of 316 V/cm, 15 fragments ranging from 50 to 500 bases were completely separated within 5.8 min in all lanes. The lane-to-lane CV of migration time was only 0.38%, and the fragment size for which the resolution per base was 0.59 was 258 +/- 15 bases (average +/-SD).

DNA, Single-Stranded↗

PubMed2005

Selective cytotoxicity of ascochlorin in ER-negative human breast cancer cell lines.

While agents targeting estrogen receptors are most effective in adjuvant therapy for human breast cancers expressing estrogen receptors after surgery, breast cancers lacking estrogen receptor are clinically serious, because they are highly malignant and exhibit resistance to the usual anti-cancer drugs, including estrogen receptor-antagonists and DNA breaking agents. Here, we found that MX-1, a human breast cancer cell line lacking estrogen receptors, exhibited higher AP-1 activity and expressed higher levels of c-Jun, c-Fos, and Fra-1 when compared with conventional estrogen receptor-positive human breast cancer cell lines. The prenylphenol antibiotic ascochlorin suppressed the AP-1 activity of MX-1 cells, and selectively killed MX-1 cells, partly due to induction of apoptosis. Our results suggest that AP-1 is an effective clinical target molecule for the treatment of estrogen receptor-negative human breast cancer.

Alkenes↗

PubMed2004

High resolution for single-strand conformation polymorphism analysis by capillary electrophoresis.

Since the successful completion of the Human Genome Project, increasing concern is being directed toward the polymorphic aspect of the genome and its clinical relevance. A form of single-strand DNA-conformation polymorphism analysis (SSCP) employing nondenaturing slab-gel electrophoresis (SGE) is applicable to the genetic diagnosis of bladder cancer from urine samples. To bring this technique into routine clinical practice, the use of capillary electrophoresis (CE) is naturally favorable in terms of speed and automation. However, the resolving power of SSCP, a prerequisite basis for reliability required in diagnostics, remains as a challenge for CE systems. We thus focused on this topic and conducted studies on CE instruments equipped with a single capillary or an array of multiple capillaries, using the resolution (Rs) as a quantitative scale for the resolving power. Polymer concentration and buffer are shown to be the decisive parameters. High Rs values of >2.5 are achieved for representative SNPs markers under the optimized conditions, without sacrificing such intrinsic advantages of CE over SGE as the 10-fold quicker migration time and operation that is reproducible, continuous, and automatic. The strategies presented broaden the limits of CE in both the current and related applications.

Buffers↗

PubMed2003

Ascochlorin derivatives as ligands for nuclear hormone receptors.

Nuclear receptor family proteins are structurally related transcription factors activated by specific lipophilic compounds. Because they are activated by a variety of hormonal molecules, including retinoic acid, vitamin D, and steroid hormones, they are assumed to be promising targets for clinical drugs. We previously found that one ascochlorin (1) derivative, 4-O-carboxymethyl-ascochlorin (2), is a potent agonist of peroxisome proliferator activated receptor gamma (PPARgamma). Here, we synthesized derivatives of 1, designated as a lead compound, to create new modulators of nuclear hormone receptors. Two derivatives, 4-O-carboxymethyl-2-O-methylascochlorin (9) and 4-O-isonicotinoyl-2-O-methylascochlorin (10), showed improved agonistic activity for PPARgamma and induced differentiation of a progenitor cell line, C3H10T1/2. We also found that 1, dehydroascofuranon (29), and a 2,4-O-diacetyl-1-carboxylic acid derivative of 1 (5) specifically activated estrogen receptors, PPARalpha, and an androgen receptor. All of the derivatives (1-29) activated the pregnane X receptor. These results suggest that the chemical structure of 1 is useful in designing novel modulators of nuclear receptors.

Alkenes↗