PubMed Health⌕ Search

Biomedical subjects

H Funakubo

Publications and source records attributed to H Funakubo.

9 recordsLinked to original sources
PubMed1998

Effect of syncytium structure of receptor systems on stochastic resonance induced by chaotic potential fluctuation.

To study a role of syncytium structure of sensory receptor systems in the detection of weak signals through stochastic resonance, we present a model of a receptor system with syncytium structure in which receptor cells are interconnected by gap junctions. The apical membrane of each cell includes two kinds of ion channels whose gating processes are described by the deterministic model. The membrane potential of each cell fluctuates chaotically or periodically, depending on the dynamical state of collective channel gating. The chaotic fluctuation of membrane potential acts as internal noise for the stochastic resonance. The detection ability of the system increases as the electric conductance between adjacent cells generated by the gap junction increases. This effect of gap junctions arises mainly from the fact that the synchronization of chaotic fluctuation of membrane potential between the receptor cells is strengthened as the density of gap junctions is increased.

Animals↗
PubMed1991

Immobilization of ultra-thin layer of monoclonal antibody on glass surface.

When preparing an affinity column and a biosensor, it is desirable to immobilize a unimolecular layer of pure protein on a matrix. In this work, we tried to immobilize a monoclonal antibody on a surface of a glass test-tube as a model, to confirm the stability of this ultra-thin layer by an enzyme immunoassay, and to estimate the thickness of the layer on a slide glass by Fourier transform infrared reflection spectrometry. A new test-tube was washed and dried. The tube was filled with 5% 3-aminopropyltriethoxysilane. The 3-aminopropylsilylated surface was treated with glutaraldehyde and 5.6.10(-2) mg/ml solution of a normal mouse monoclonal antibody. The Schiff base between glutaraldehyde and the antibody was further reduced with 7.9.10(-3)% NaBH4. The tube was washed with 0.05% Tween 20 to block non-specific binding. The antibody immobilized on the surface was measured by an enzyme immunoassay based on a reaction of anti-mouse immunoglobulin G labelled with alkaline phosphatase, with which p-nitrophenol was produced from p-nitrophenylphosphate as a substrate. Meanwhile, various amounts of the antibody were immobilized on slide glasses in the same manner. The antibody on each surface was measured by Fourier transform infrared reflection spectrometry. The antibody immobilized under the final conditions was detectable by the enzyme immunoassay, and stable at 4 degrees C for ten days. The antibody on the slide glass was a unimolecular layer, as judged from the Fourier transform infrared spectra referred to -CONH- band semiquantitatively. Thus, we found the optimal conditions for immobilizing an ultra-thin layer of the monoclonal antibody on the glass surface.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Development of a new microsurgical robot for stereotactic neurosurgery.

The robot technology was introduced into a new stereotactic neurosurgery system for applications to biopsy, blind surgery, and functional neurosurgery. The authors have developed a newly designed prototype microsurgical robot, designed to allow a biopsy needle to reach the target such as a cerebral tumor within a brain automatically on the basis of the X, Y, and Z coordinates obtained by CT scanner. This robot is so small that it can be driven in a CT scanner gantry. It consists mainly of the link mechanism and the insertion mechanism. We constructed the link mechanism and investigated its working space.

Biopsy, Needle↗
PubMed1990

Configuration of a robot dedicated to stereotactic surgery.

The design of a robot for functional stereotactic surgery which is under construction in our laboratory is described. The main features include operation inside the computed tomographic (CT) scanner, the possibility of intraoperative CT scanning and complete handling of the stereotactic probes by the robot.

Brain Diseases↗
PubMed1988

Development of motion analyzing system for implanted tilting disk valves.

A motion-analyzing system was developed to quantitatively evaluate functions of the implanted tilting disk valve, e.g., an open angle and a duration of valve open and/or shut. In this system a picture of the valve on an x-ray cinefilm is displayed on the CRT screen by the TV camera for extraction of valve position. Data extracted are stored in the computer and are used to calculate parameters for motion analysis of the valve. The reliability of this system was confirmed within 3 degrees of error using the valve model prior to the evaluation of cinefilms clinically procured. With the aid of this motion analyzing system, complicated motions of the tilting disk valve were easily quantified and the useful information as given for clinical diagnosis and further valve development.

Computer Graphics↗
PubMed1987

Pasteurella multocida endophthalmitis after a cat bite.

We treated a patient with Pasteurella multocida endophthalmitis associated with a retinal detachment resulting from a cat bite. To our knowledge, endophthalmitis from an animal bite has not been described previously. Organisms were directly inoculated from a perforated wound through the globe. The patient was vigorously treated with intensive systemic antimicrobial chemotherapy and pars plana vitrectomy. The inflammation subsided after repeated vitrectomies. A subsequent retinal detachment was treated with fluid-gas exchange and 360 scleral buckling with a silicone implant. Eight months after surgery the visual acuity was 40/200.

Animals↗