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Biomedical subjects

Y Kosugi

Publications and source records attributed to Y Kosugi.

At least 37 records · Page 2Linked to original sources
PubMed1997

New sandwich ELISA for human urinary N-acetyl-beta-D-glucosaminidase isoenzyme B as a useful clinical test.

We have developed a new ELISA for quantifying N-acetyl-beta-D-glucosaminidase (NAG) isoenzyme B in human urine after raising monoclonal antibodies against the isoenzyme from human placenta. Though the obtained antibodies reacted not only to isoenzyme B but also to A, we could detect isoenzyme B selectively by a two-step sandwich ELISA with a pair of selected antibodies at low pH in the first reaction. The detected limit was 0.5 microgram/L for a sample volume of 25 microL. Within-run CVs ranged from 2.5% to 5.4% and between-run CVs ranged from 6.2% to 9.1%. Recoveries of NAG isoenzyme B added to each of three urine samples ranged from 91% to 114%. The dilution curves of urine samples showed good linearity. The cross-reactivity of NAG isoenzyme A was practically negligible (2-3%). The mean value for NAG isoenzyme B in spot urines from healthy adults was 2.9 micrograms/g creatinine. This ELISA method is rapid and precise enough for routine determination of NAG isoenzyme B in human urine.

Acetylglucosaminidase↗
PubMed1997

Neural network-based PET image reconstruction.

In PET image analysis, conventional deconvolution alone will not give sufficient information for a precise study of a localized brain function. In the deconvolution process, which is a type of inverse problem, it is important to confine the solution space by incorporating a priori knowledge such as the tissue distribution given by MR images as well as smoothness in the blood flow distribution profile. An MR-embedded neural-network model is described to reduce the partial volume effect in the restoration of blood flow profiles from PET images.

Brain↗
PubMed1996

[Usefulness of newly developed subcutaneous one point lifting method in gynecological laparoscopic operation].

We first introduced the abdominal wall lifting method in gynecological laparoscopic operations in 1994. Now we have developed a new one-point lifting technique (Tokyo Medical College method) that enables gynecological laparoscopic operations to be performed more safely, easily and economically. 1. The TMC method provides a sufficiently spacious operative field in the same way as artificial pneumoperitoneum and can overcome the negative influence of obesity on the operative field. 2. Because the abdominal wall is lifted up by means of a single stainless steel wire passed under the skin in this method, the limitations of previous methods are completely overcome. Furthermore setting up for this method is very easy and can be completed in a short time. 3. Because the aperture for the Surgigrip made in the abdominal wall is short and has a large internal diameter, we can manipulate operative instruments freely. Especially suturing and ligation can be carried out simply and accurately. 4. We were able to continue irrigation and suction without deterioration of the operative field and to easily remove resected tissue from the abdominal cavity. 5. The frequency of intracorporeal suture and ligation in this method increased significantly compared with the pneumoperitoneum method in cases of ovarian diseases. As a result, most operative procedures in ovarian diseases became cystectomies, preserving the healthy part of the ovary. This also reduced operative cost by avoiding expensive autosuture equipment. 6. There were no complications such as subcutaneous bleeding with this method. There was no significant difference between this method and pneumoperitoneum in terms of postoperative pain. The TMC method is a new laparoscopic operative technique that allows procedures to be performed under conditions close to laparotomy procedures and solves most of the problems of the pneumoperitoneum method.

Abdominal Muscles↗
PubMed1996

[Analysis of the mechanism of trophoblast infiltration].

A cytotrophoblast (CT) infiltrates into the stroma, forming an extravillous trophoblast (EVT) in the placenta early in gestation and the phenomenon is strictly controlled, differing from the infiltration of cancer cells. The expression of matrix metalloproteinase 2 (MMP2) and matrix metalloproteinase 9 (MMP9), which deeply involve infiltrative metastasis of cancer, and the reactivity to transforming growth factor beta 1 (TGF beta 1), which controls the expression of these MMPs and inhibits the growth of epithelial cells, were investigated in CT derived from villi at normal gestational week 6 (early CT) and CT derived from villi at normal gestational week 37 (full-term CT), and also the choriocarcinoma cell line BeWo (BeWo). The ability of normal epithelial cells and BeWo cells to proliferate and infiltrate were evaluated in vitro by northern blotting, gelatin zymography, and invasion assay. It was revealed that early CT had a higher capacity for infiltration than full-term CT as well as BeWo. MMP2 and MMP9 appeared in the early CT, whereas only MMP9 was observed in the full-term CT. MMP2 and MMP9 were more abundantly observed in the early CT and the full-term CT rather than in BeWo. In uterine stroma-derived cells, membrane type matrix metalloproteinase (MT-MMP), which activates MMP2, was observed. These results indicated that the motility of normal villous cells was higher in the early CT than in the full-term CT. The expression of MMP2 in the early CT, which was not observed in the full-term CT, was thought to be related to this difference in motility. As for the responsiveness to TGF beta 1, which is a growth inhibiting factor for epithelial cells, the villous carcinoma cell line was insensitive to the growth inhibiting effect of TGF beta 1, but the early CT was sensitive to this effect. When TGF beta 1 was added, MMP2 and MMP9 increased in the early CT. This response was also seen in BeWo. That is, it was assured that the growth capacity was not inhibited in BeWo, but was certainly inhibited in the early CT. The overall results of these evaluations indicated that the development to EVT by infiltration of the early CT was associated with the increase in the mobility of cells caused by MMP2 and the increase in amounts of MMP2 and MMP9 caused by TGF beta 1, and the predominant inhibitory effect of TGF beta 1 on the growth of normal epithelial cells could explain why normal epithelial cells do not grow as cancer cells do.

Animals↗
PubMed1993

Changes in the parameters of oxygen metabolism in a clinical course recovering from potassium cyanide.

Poisoning with potassium cyanide is usually fatal because of the inhibition of cytochrome oxidase. The parameters of oxygen metabolism in a patient with cyanide poisoning who was admitted in a coma with seizures was monitored. The administration of amyl nitrite and sodium thiosulfate led to a rapid improvement: the parameters reflecting oxygen metabolism improved and the plasma level of cyanide decreased. The patient revived 1 1/2 hours after treatment. The arterial ketone body ratio (AKBR), which is the ratio of acetoacetate to beta-hydroxybutyrate in arterial blood and which reflects the redox state in liver mitochondria, improved dramatically following treatment. Because the AKBR changes in relation to electron transport in liver mitochondria, it seems to be a logical parameter for evaluating the effect of potassium cyanide poisoning on electron transport. The AKBR also reflects the efficacy of treatment for cyanide poisoning.

3-Hydroxybutyric Acid↗
PubMed1992

A biocompatible needle-type glucose sensor based on platinum-electroplated carbon electrode.

A biocompatible needle-type glucose sensor with a 3-electrode configuration was constructed. A platinum-electroplated carbon stick was used as the working electrode, Ag/AgCl as the reference electrode, and a disposable hypodermic needle made of stainless steel as the counter electrode. A Nafion membrane, an immobilized glucose oxidase (GOD) membrane, and a biocompatible membrane with diffusion-limiting effect were coated successively onto the working electrode. The sensor showed a rapid response (< 120 s in batch operation), good reproducibility (RE < 3%), good stability (over 36 h in control serum), a wide dynamic range (5-600 mg/dL glucose), and superior biocompatibility. It was used to determine glucose in serum. The data obtained from the sensor showed good agreement with that from a clinical autoanalyzer (R > 0.95).

Biocompatible Materials↗
PubMed1991

Open surgery assisted by the neuronavigator, a stereotactic, articulated, sensitive arm.

A new computed tomographic-stereotactic device that translates the operating point onto preoperative computed tomographic (CT) images, the Neuronavigator, has been developed. We have applied this system to various neurosurgical procedures to examine its usefulness. The system consists of a 6-joint sensing arm and a 16-bit personal computer. It projects the location of the arm tip onto a corresponding CT slice with a cursor that guides the surgeon toward the intracranial target during open surgery. The system also projects the location of the tip onto angiograms, and when used in conjunction with echography or a transcranial Doppler (TCD) flow meter, the surgeon's ability to navigate is enhanced. Sixty-eight patients underwent operation with the Neuronavigator. The navigation system worked as the core of a multimodal three-dimensional data base that proved to be useful during surgery. The maximum detection error was 2.5 mm, which was considered sufficient for open microsurgery. It also proved useful in designing the position of a craniotomy, in targeting deep-seated mass lesions, and in tracing the tumor edge, which had been identified on a CT scan. When the angiogram was combined with the navigator, it became easy to identify key vessels within a small operating field. The system was also combined with a TCD flow meter. This combination makes it possible to translate the measuring point of the TCD directly into CT coordinates, improving the precision of location of the TCD probe. The Neuronavigator combines various diagnostic images into one database and effectively guides the surgeon during surgery.

Adolescent↗
PubMed1990

New tetrapolar circuit method using magnetic field for measurement of local impedance change in biological substances.

A new tetrapolar circuit method using a magnetic field is proposed to measure the local electric impedance change in living tissue. Based on this method, we designed an apparatus which can detect impedance changes in closely-situated two parts of living tissue, simultaneously and independently. Using this apparatus, we showed the effectiveness of the proposed method by an in vitro experiment and by an in vivo measurement of pulsatile waveforms in the forearm arteries. The detection sensitivity for a local impedance change was confirmed to be higher than that of the conventional tetrapolar method. Pulsatile impedance waveforms measured in the radial and the ulnar parts of the forearm were consistent with those estimated from the anatomical structure.

Arteries↗
PubMed1989

Phase conjugation model for information transfer in the nervous system.

In the nervous system, dispersion in propagation time sometimes brings delay distortion or phase distortion on the information transmission. Also in the memory retrieval processes in the brain, some parts of images may be retrieved more slowly than others. For smooth control of fast movements as well as for keeping exact thinking, these distortions have to be taken out. To understand the distortion cancelling mechanism, new neural network models for compensating the phase distortion are proposed. The models stand on the concept of "phase conjugate mirror" which is used in optical image processing. Simulation studies based on the model resulted in successful cancellation of the delay dispersion involved in the information transmission in the nervous system.

Computer Simulation↗
PubMed1989

[Ultrasonic tissue characterization by spectral analysis of myocardial textural pattern].

Based on the fact that ultrasonic myocardial textural patterns are more irregular in the pathological myocardium than in the normal, evaluation of the myocardial tissue character was attempted in vivo using spectral analysis. Parasternal left ventricular long-axis echocardiograms were obtained from five patients with old myocardial infarction diagnosed by history, electrocardiography and coronary angiography. These echocardiograms were transferred to an image analyzer and digitized (256 x 256 x 8). The waveforms of the gray-scale-changes from the normal myocardium showed periodicity in each 8-pixel cycle, but those from the infarcted myocardium did not. To quantify pattern changes in gray-scale values in the ultrasound beam direction, spectral analysis was performed by the maximum entropy method (MEM). There were four peaks in the MEM spectra both in the normal and infarcted myocardia, but there was a great significance in these patterns: with high, steep peaks in normal MEM spectra, and low, blunt peaks in infarcted ones. By discriminatory analysis of these four peak values, normalized by the whole spatial frequencies as multivariate, the misclassification rate was 4.8-22.7% in anteroseptal infarctions and 5.0-20.0% in posterior infarctions. Thus, spectral analysis of the myocardial textural pattern has advantages for analyzing routine echocardiograms without corrections by any absolute ultrasonic references. Furthermore, the misclassification rate is so low that we are able to characterize myocardial tissue.

Echocardiography↗
PubMed1989

[A tetrapolar circuit method using magnetic field for biological resistivity measurement].

A local impedance and its change were measured using a tetrapolar circuit combined with magnetic eddy current generator. By this method, current distribution can be restricted to a desired part, so as to eliminate errors due to uncertainty of the resistance between the electrode and the skin. The resistivity of a substance in a biological model measured by this method was nearly equal to that of the substance separated from the model. Sensitivity and localization were assessed in the other model composed of a piece of metal plate in a saline pool. The detection sensitivity was validated theoretically. The localization of the impedance pulsatile waveforms, measured at the proximal part of the forearm, was consistent with that of the arteries at this part. These results suggest that this method using eddy current should expand the application area of bio-impedance measurements.

Electric Conductivity↗
PubMed1988

An interactive multivariate analysis of FCM data.

The procedure and results of the interactive multivariate analysis of FCM data are described. Using principal-components analysis, cluster analysis, and interactive maneuvers, this procedure facilitates an effective data compression from a four-dimensional space into two-dimensional space, then allows cluster separation. The procedure is especially effective for separating clusters, which are degenerated in the usual scattergrams. Programs were mostly written in C language on MS-DOS and were tested on four-dimensional analysis of the blood cells, which resulted in a successful separation of the degenerated clusters.

Cell Separation↗
PubMed1988

Effect of interferon-beta on the cell cycle of human glioma cell line U-251 MG: flow cytometric two-dimensional (BrdU/DNA) analysis.

This paper describes the determination of the effect of IFN-beta on U-251 MG cells using the bromodeoxyuridine (BrdU/DNA) analysis technique. The cell cycle perturbation of exponentially growing cells was estimated by a newly developed two-dimensional analysis of sequential BrdU/DNA distributions measured at 4-hr intervals after IFN-beta administration. The U-251 MG cell line was sensitive to IFN-beta, and cell proliferation was inhibited by 50.0% at 48 hr. Analysis of DNA histograms indicated that IFN-beta accumulated the cells in the S-phase, from 16 to 48 hr after treatment. In the two-dimensional analysis, labeled cells treated with IFN-beta moved from the S-phase through the G2M-phase and then entered the G1-phase within 12 hr after the initial treatment, in a pattern similar to labeled cells untreated with IFN-beta. After 16 hr, labeled cells treated with IFN-beta began to accumulate in the S-phase and remained there even after 48 hr. These results imply that IFN-beta may have an effect on the G1-phase, thereby inducing S-phase accumulation of human glioma cell line U-251 MG.

Bromodeoxyuridine↗