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Biomedical subjects

Yasuo Wada

Publications and source records attributed to Yasuo Wada.

7 recordsLinked to original sources
PubMed2005

High efficiency electrochemical immuno sensors using 3D comb electrodes.

To realize highly sensitive electrochemical immunoassays, a micro-fabricated three-dimensional (3D) electrode was fabricated and applied to enzyme immuno assay based on production of a redox species. The dimensions of the electrodes are 10 microm in width and 30 microm in height, with 20 microm spacing in between, and the 30 pairs of anode and cathode electrodes made up a single sensor. This structure lead to enhancement of the electrochemical reaction, nearly 100% of trap ratio of redox species. It can be applied to highly sensitive enzyme immuno sensing based on p-aminophenylphosphate (PAPP). Applicability of this technique to the immuno assay for one of the clinical diagnostic marker proteins (alpha-fetoprotein; AFP) from 6 to 500 ng/mL was demonstrated.

Biological Assay↗
PubMed2004

Primary osteosarcoma of the breast.

We report a case of primary osteosarcoma of the breast, which is a rare histological type of all breast tumors. A 58-year-old woman had noticed a right breast mass long before presenting to our hospital because it had gradually increased in size. The mass was bony-hard, 90 x 70 mm in size, and was located mainly in the upper outer quadrant of the left breast. Mammography demonstrated a round radiopaque mass with a shaggy outline. There were small bone metastases to the pelvis and scapula on bone radionuclide scan, but no other metastasis was observed with subsequent investigations. Modified radical mastectomy including axillary lymph node dissection was performed. Histologically, the excised tumor was consistent with extraskeletal osteosarcoma of the breast accompanied by lymph node metastses. In spite of adjuvant chemotherapy, the patient suffered a local recurrence four months later and died of aggressive multiple metastases 7 months after surgery.

Bone Neoplasms↗
PubMed2002

Transmission laser microscope using the phase-shifting technique and its application to measurement of optical waveguides.

A type of a transmission phase-shifting laser microscope, believed to be new, has been developed. In this microscope a biprism located between a magnifying lens and an observation plane was used as a beam splitter. The biprism is laterally translated to introduce phase shifts required for quantitative phase measurement with a phase-shifting technique. The disturbance caused by a Fresnel-diffracted wave from the splitting edge of the biprism is reduced by placement of a linear beam stopper at the center of an intermediate image plane. As the first application, the developed microscope is used to measure a refractive-index distribution in optical waveguides. A difference of refractive indices of less than 6 x 10(-5) is clearly measured in the submicrometer region.

Journal Article↗
PubMed2002

Estimation of surgical costs using a prediction scoring system: estimation of physiologic ability and surgical stress.

HYPOTHESIS: Our predictive scoring system, Estimation of Physiologic Ability and Surgical Stress, can estimate surgical costs. DESIGN: Multicenter cohort study for 1 year. SETTING: Six national hospitals in Japan. PATIENTS: A consecutive series of 929 patients who underwent elective gastrointestinal operations. MAIN OUTCOME MEASURES: The preoperative and the comprehensive risk scores of the Estimation of Physiologic Ability and Surgical Stress were determined preoperatively and immediately after the operation, respectively. Estimated costs were computed using the following equation: costs = US $10,160 + (US $13,470 x comprehensive risk score). Data on length of stay, costs for surgical admission, and severity of postoperative complications were collected at hospital discharge. RESULTS: The comprehensive risk score significantly correlated with the severity of the postoperative complications (Spearman rank correlation = 0.54, P<.001), the length of stay (Spearman rank correlation = 0.69, P<.001), and the costs (Spearman rank correlation = 0.72, P<.001). The ratio of real to estimated costs varied from 0.82 to 1.17 at the various ranges of the comprehensive risk score, resulting in 0.93 in the total 929 patients. This ratio varied from 0.71 to 1.12 among the hospitals, the smallest of which was attributed to the hospital that primarily used the clinical pathways. A significant increase in the costs was observed according to the preoperative risk score for open colectomy (P =.009) and distal gastrectomy (P =.002). When we simulated the hospital revenue where different payment rates were set according to the preoperative risk score, the revenue seemed to improve in the hospitals that treated more high-risk patients, compared with the fixed payment system. CONCLUSION: The Estimation of Physiologic Ability and Surgical Stress scoring system may be useful for estimating surgical costs, making a benchmark analysis, and determining the rate in a risk-based payment system.

Adolescent↗
PubMed2002

Prospects for single-molecule information-processing devices for the next paradigm.

Present information technologies use semiconductor devices and magnetic/optical disks; however, they are all foreseen to face fundamental limitations within a decade. Therefore, superceding devices are required for the next paradigm of high-performance information technologies. The paper first describes architectures suitable for single-molecule information processing, in which it is claimed that the performance of information processing is higher if speed and element number product is larger in almost all known architectures. Thus, single-molecule information-processing devices should be the most appropriate approach for the next paradigm. Then, prospects for single-molecule devices suitable for future information-processing technologies are described. Four possible milestones for realizing the Peta/Exa-floating operations per second (FLOPS) personal molecular supercomputer are proposed. Current status and necessary technologies of the first milestone are described, and necessary technologies for the next three milestones are also discussed.

Computers↗
PubMed2002

[Three cases of advanced gastric cancer treated by TS-1 in combination with low-dose cisplatinum].

TS-1, a DPD inhibitory fluoropyrimidine, is a novel oral formation of 5-fluorouracil (5-FU). In patients with advanced gastric cancer, the response rate was reportedly over 40%. We report three cases of advanced gastric cancer treated using TS-1 in combination with a low-dose of cisplatinum (CDDP) that well responded. Case 1: A 62-year-old women underwent total gastrectomy. Ten weeks later, she suffered intestinal obstruction due to peritoneal recurrence of gastric cancer. Eighty mg of TS-1 in combination with bi-weekly administration of CDDP (10 mg) improved her intestinal obstruction. Case 2: A 50-year-old man suffered peritoneal recurrence of gastric cancer. Computed tomography (CT) showed intestinal obstruction, ascites, and hydronephrosis. After 100 mg of TS-1 in combination with bi-weekly administration of CDDP (20 mg) for 1 year, CT showed almost complete improvement of peritonitis carcinomatosa. Case 3: A 58-year-old man, who suffered advanced gastric cancer with peritonitis carcinomatosa, was administrated 100 mg of TS-1 in combination with bi-weekly administration of CDDP (20 mg). After 2 months of administration, remarkable improvement was observed in the upper gastrointestinal series. Adverse reactions, which were grade 1 for stomatitis, were observed only in case 1. All three patients are alive (case 1 and 2 have survived more than one year) and therapy is continuing. In conclusion, combined chemotherapy of TS-1 and low-dose CDDP was effective and well tolerable for advanced gastric cancer patients. It was suggested that effective biochemical modulation might be achieved by these two drugs.

Adenocarcinoma↗