Biomedical subjects

Tomiya Abe

Publications and source records attributed to Tomiya Abe.

5 recordsLinked to original sources

PubMed2006

Aberration properties in a chirped grating for coarse wavelength division demultiplexing.

We studied the imaging performance of a chirped grating for a demultiplexer designed for coarse wavelength division multiplexing using a wavefront aberration analysis and the ray tracing simulation. The demultiplexer was composed of a chirped grating, cylindrical lenses, and a waveguide. The best image point and the spot shape focused by the chirped grating were effectively calculated with the wavefront aberration. We applied the aberration analysis to design a waveguide to connect branched beams to photodetectors, and we confirmed the demultiplexing performance experimentally.

Journal Article↗

PubMed2005

Bidirectional optical coupler for plastic optical fibers.

We have developed a low-loss bidirectional optical coupler for high-speed optical communication with plastic optical fibers (POFs). The coupler, which is fabricated by an injection molding method that uses poly (methyl methacrylate), has an antisymmetric tapered shape. We show that the coupler has low insertion and branching losses. The tapered shape of the receiving branch reduces beam diameter and increases detection efficiency coupling to a photodetector, whose area is smaller than that of the plastic optical fiber. The possibility of more than 15-m bidirectional transmission with a signaling bit rate up to 500 Mbits/s for simplex step-index POFs is demonstrated.

Journal Article↗

PubMed2004

Study of plasma exchange for liver failure: beneficial and harmful effects.

Plasma exchange (PE) is often performed in combination with hemodialysis (HD) or hemodiafiltration. However, most methods were developed for the treatment of renal failure, so various problems may arise during treatment of liver failure (LF). In this study, we investigated the impact of PE alone and in combination with HD, and we assessed the complications of using PE + HD for the treatment of LF. After the exchange of 1 L of fresh frozen plasma (FFP), we measured serum electrolytes, HCO(3) (-), citrate, and acetate at 3 points in the circuit: A) the plasma separator inflow; B) after mixing of FFP/the dialyzer inflow; and C) the dialyzer outflow. Serum levels of human hepatocyte growth factor (HGF), acetate, and citrate were also measured before and after PE + HD. The levels of K(+), Ca(++), HCO(3) (-), and acetate were significantly decreased, and citrate was increased, between A and B. K(+) and citrate were decreased, while Ca(++), HCO(3) (-), and acetate showed an increase between B and C. Comparison of A with C revealed insufficient correction of the Ca(++) and citrate levels by HD. After PE + HD, serum levels of acetate and citrate were increased, while HGF was decreased. We concluded that i) when PE is performed, HD is also necessary for correction, but achieves insufficient correction of Ca(++) and citrate, ii) PE is non-selective and not only removes toxins but also beneficial substances such as HGF, iii) accumulation of acetate occurred, even with bicarbonate dialysate, since it also contains acetate for acidification.

Acetates↗

PubMed2003

Effect of beta(2)-microglobulin adsorption column on dialysis-related amyloidosis.

BACKGROUND: beta2-microglobulin (beta2-m) is considered a major pathogenic factor in dialysis-related amyloidosis (DRA), often seen in long-term dialysis patients. No effective therapy for this severely debilitating disease is currently available. Lixelle, an adsorption column, has been developed for the elimination of beta2-m; the efficacy of this column has been evaluated in this study. METHODS: Seventeen hemodialysis patients with DRA were first treated with high-flux dialysis for a minimum of 1 year. This was followed by 1-year treatment with Lixelle column connected in series to the high-flux dialyzer. Treatments were used three times a week for both phases of this study. During the study period, beta2-m, pinch strength, motor terminal latency, and activities of daily living were evaluated. RESULTS: After 1-year treatment with high-flux dialysis the beta2-m level remained unchanged; however, after 1-year treatment with the addition of the Lixelle column, beta2-m level decreased significantly from 34.5 +/- 8.4 mg/L to 28.8 +/- 7.3 mg/L (P < 0.05). After 1 year of Lixelle column use, the pinch strength increased from 6.8 +/- 4.7 pounds to 9.1 +/- 5.5 pounds (P < 0.01), and the median motor terminal latency was significantly reduced from 5.1 +/- 1.0 mseconds to 4.5 +/- 1.1 mseconds. A significant improvement was also observed in the activities of daily living score of the upper extremities. CONCLUSION: These results suggest that the addition of Lixelle to the high-flux dialyzer is associated with a significant clinical improvement in DRA patients.

Adsorption↗

PubMed2002

Improvements in artery occlusion by low-density lipoprotein apheresis in a patient with peripheral arterial disease.

Peripheral arterial disease (PAD; arteriosclerosis obliterans) shows ischemic symptoms along the peripheral arteries due to reduced blood flow, and the number of patients with PAD is increasing. Several papers have reported on the clinical effect of low-density lipoprotein apheresis (LDL-A) on PAD, but there has been no report so far on the improvement of total peripheral artery stenosis by LDL-A. We report on the clinical course of a female PAD patient with intractable decubitus in her heel due to the complete occlusion of anterior tibial artery who was treated by a series of LDL-A sessions. The complete occlusion of the anterior tibial artery improved as seen on angiography, and the decubitus in her heel also markedly improved after LDL-A therapy. This report supports the clinical benefit of LDL-A for the treatment of PAD.

Aged↗