Diagnostic ability of high-frequency ultrasound probe sonography in staging early gastric cancer, especially for submucosal invasion.

BACKGROUND: Advances in gastrointestinal endoscopy have resulted in endoscopic mucosal resection becoming the main therapy for many early gastric cancers confined to the mucosa and, in some cases, of minimal submucosal invasion. Thus, preoperative determination of the depth of the cancer is important. We compared the results of high-frequency ultrasound probe sonography with those of histologic study to clarify the usefulness of identifying of submucosal invasion and determining the depth of early gastric cancer. METHODS: Subjects were 295 patients diagnosed with early gastric cancer who had undergone endoscopic mucosal or surgical resection. High-frequency ultrasound probe sonographic findings were compared with histologic findings. RESULTS: The muscularis mucosae was visualized in 63% of cases of early gastric cancer. By construction on receiver operator characteristics curve, we determined that submucosal invasive cancer could be diagnosed by high-frequency ultrasound probe sonography to a depth of about 600 microm. There was no case in which invasion deeper than 1000 microm was diagnosed as a hypoechoic area limited to the mucosal layer or a fan-shaped hypoechoic area in the submucosal layer. The depth of early gastric cancer was accurately determined in 90% of cases. CONCLUSIONS: High-frequency ultrasound probe is a useful tool for accurately determining the depth of invasion of early gastric cancer when its limitations are understood.

Microfabricated silicon dioxide cantilever with subwavelength aperture.

We have developed a microfabricated SiO2 cantilever with subwavelength aperture for scanning near-field optical microscopy (SNOM), to overcome the disadvantages of conventional optical fibre probes such as low reproducibility and low optical throughput. The microcantilever, which has a SiO2 cantilever and an aperture tip near the end of the cantilever, is fabricated in a reproducible batch process. The circular aperture with a diameter of 100-150 nm is formed by a focused ion-beam technique. Incident light is directly focused on the aperture from the rear side of the cantilever using a focusing objective, and high optical throughput (10(-2) to 10(-3)) is obtained. The microcantilever can be operated as a SNOM probe in contact mode or in dynamic mode.

Optical microcantilever consisting of channel waveguide for scanning near-field optical microscopy controlled by atomic force.

We develop a novel optical microcantilever for scanning near-field optical microscopy controlled by atomic force mode (SNOM/AFM). The optical microcantilever has the bent channel waveguide, the corner of which acts as aperture with a large tip angle. The resonance frequency of the optical microcantilever is 9 kHz, and the spring constant is estimated to be 0.59 N/m. The optical microcantilever can be operated in contact mode of SNOM/AFM and we obtain the optical resolution of about 200 nm, which is as same size as the diameter of aperture. We confirm that the throughput of optical microcantilever with an aperture of 170 nm diameter would be improved to be more than 10(-5).

Polarization properties of bent-type optical fibre probe for magneto-optical imaging.

Quantitative evaluation of magneto-optical parameters is necessary in order to apply scanning near-field optical microscope (SNOM) technology to the study of magnetism on the mesoscopic scale. For this purpose, quantitative knowledge of polarization transmission properties through an optical fibre probe is required. We therefore determined the Stokes parameters of the bent-type optical fibre probe that is used as a cantilever for atomic force microscope operation in our SNOM system. As a result, it is found that the degree of polarization is maintained in the light emitted from the probe, although the probe acts as if it were a wave plate. This anisotropic polarization state of the light emitted from the probe was compensated for by using a Berek compensator placed in front of the fibre coupler.

Effects of the new antiplatelet agent 2-methyl-3-(1,4,5,6-tetrahydronicotinoyl)pyrazolo[1,5-a]pyridine on platelet aggregation and thrombosis in experimental animals.

Antiplatelet and antithrombotic effects of KC-764 (2-methyl-3-(1,4,5,6-tetrahydronicotinoyl)pyrazolo[1,5-a]pyridine, CAS 94457-09-7) were studied. KC-764 inhibited arachidonic acid (AA)- and collagen-induced platelet aggregation with IC50s of 1.0 x 10(-8)-2.8 x 10(-7) mol/l for humans, rabbits, guinea pigs and dogs, and IC50s of 3.9 x 10(-6)-3.7 x 10(-5) mol/l for mice and rats in vitro. KC-764 inhibited AA- and collagen-induced aggregation with ID50s of 0.04-0.09 mg/kg p.o. in rabbits and dogs, and ID50 of 13.0 mg/kg p.o. in rats. These antiaggregatory activities of KC-764 were stronger than those of acetyl-salicylic acid (ASA), indometacin, cilostazol and ticlopidine. KC-764 inhibited the production of thromboxane B2 (TXB2) in rabbit platelet microsomes, washed platelets and reconstituted platelet rich plasma (RPRP) with IC50s of 2.9 x 10(-6) mol/l, 2.8 x 10(-7) mol/l and 4.3 x 10(-8) mol/l, respectively. The in vitro inhibitory activity of KC-764 on AA-induced platelet aggregation was more potent when RPRP was used rather than washed platelet suspension containing 30% rabbit plasma. ASA did not show such an augmentation. KC-764 prevented collagen- and AA-induced thrombosis at more than 1 mg/kg p.o. and more than 0.1 mg/kg i.v. in mice and rabbits. KC-764 showed the wider margin of dose between antiplatelet action and prolongation of bleeding time in rabbits than ASA and indometacin. These results indicated that KC-764 was a potent antithrombotic drug to prevent TXB2 production and less possible to induce untoward actions as compared with ASA or indometacin.

Optical pattern recognition of letters by a joint-transform correlator using a ferroelectric liquid-crystal spatial light modulator.

The use of a joint-transform correlator (JTC) as an optical pattern-recognition system for letters has been studied. The system incorporates a ferroelectric liquid-crystal spatial light modulator (LAPS-SLM). The LAPS-SLM has a high contrast ratio and a fast response time, permitting the JTC to recognize more reference letters simultaneously than a classical correlator can.