Biomedical subjects

Y Yamakoshi

Publications and source records attributed to Y Yamakoshi.

42 records · Page 3Linked to original sources

PubMed1993

Enamelins in the newly formed bovine enamel.

The possibility of using the antisera raised in rabbits against the porcine 25 kDa amelogenin, 32 and 89 kDa enamelins, and the 13-17 kDa nonamelogenin for the differentiation and identification of the protein components in bovine immature enamel was examined. Although the immunoreactivities of these antisera against bovine enamel proteins were weaker than those against the porcine proteins, it was found that these antisera could differentiate and demonstrate immunohistochemically a characteristic distribution of three different kinds of enamel protein components in the bovine secretory stage enamel similar to those observed in the porcine immature enamel. Of the several high molecular weight proteins being reactive to the anti-porcine 32 and 89 kDa enamelin sera, the 130 kDa protein, having the highest molecular weight, was extracted and purified from the bovine enamel sample which was obtained by peeling approximately 30-microns thickness of the outermost layer of the secretory stage enamel. The amino acid composition of the 130 kDa protein was similar to the known bovine enamelins, and was rich in aspartic acid, glutamic acid, proline, and glycine. The results could suggest that the enamelins of lower molecular weight than this protein, which are found in the bovine secretory stage enamel, are derived from this precursor protein.

Amelogenin↗

PubMed1993

Measurement of fetal movements using multichannel ultrasound pulsed Doppler: autorecognition of fetal movements by maximum entropy method.

Changes in fetal movements indicate biophysical conditions and functional development. The precise evaluation of fetal movements in clinical medicine requires the development of a continuous automated monitoring technique. A basic study of the measurement of fetal movements was carried out by modifying the Doppler ultrasound module of a cardiotocograph to produce low-frequency Doppler signals and five simultaneous outputs at various depths. These outputs represent displacement inside tissue at the various depths. Signal processing was executed on a 32-bit computer with a high-accuracy displacement estimation technique using the arctangent method. Results showed successful tracking of minute movements, such as fetal breathing movements (FBM), while rejecting other movements derived from maternal breathing etc. Using spectral analysis by the maximum entropy method (MEM), fetal movements were classified in three groups (FBM, fetal gross movements (FGM) and fetal heart movements (FHM), based on the character of their special peak frequencies. The order of movement recognition was first FGM, then FBM and lastly FHM. FBM were more successfully recognised by MEM than by conventional B-mode observation methods. Small body movements were difficult to recognise as FGM by MEM in some cases. Although further studies are required for clinical application, it appears that automated assessments of fetal movements should be possible with this technique.

Female↗

PubMed1992

Isolation and characterization of macrocarpals B--G antibacterial compounds from Eucalyptus macrocarpa.

Six novel phloroglucinol dialdehyde diterpene derivatives (macrocarpals B--G), which have antibacterial activity, were isolated from leaves of Eucalyptus macrocarpa. These compounds have closely related structures, the molecular formula for B--F being C28H40O6, and that of G being C28H38O5. The structures of macrocarpals B, D, and G were analyzed by means of NMR analyses.

Anti-Bacterial Agents↗

PubMed1992

[Development of a fetal breathing movement tracking system using pulsed Doppler ultrasound].

Fetal breathing movements (FBM) form a useful means of monitoring fetal conditions and functional development. To develop a continuous and quantitative FBM monitoring system for clinical use, a non-imaging method using pulsed Doppler was devised. A pulsed Doppler cardiotocograph module was extended to obtain low frequency Doppler signals, by the addition of a 90 degree phase shifter, analog multipliers, quadrature detector, sample and hold circuits and low pass filters, to produce five simultaneous outputs representing movement at depths separated by 1.5cm intervals. These outputs represent the displacement inside tissue at the various depths. Signal processing was executed on a 32-bit computer with an A/D converter. On-line processing by means of a zero-crossing method and off-line arc tangent method with high accuracy displacement estimation were applied for calculation. With this system, FBM was detected as cyclic and regular displacements of a few hundred microns ranging from 0.5 to 1.5Hz. With digital signal processing of 2/3Hz high pass filtering, precise evaluation FBM was possible while rejecting gross movements due to maternal breathing, etc. Although further studies are required for clinical application, it appears that quantitative assessments of FBM should be possible with this technique.

Female↗

PubMed1991

Tracking of fetal breathing movements by pulsed Doppler ultrasound.

Fetal breathing movements form a useful means of monitoring fetal conditions and functional development. Precise quantitative evaluation of fetal breathing movements requires the development of a continuous automated technique. A preliminary study of Doppler signals due to fetal breathing movements was carried out using a cardiotocograph in which the normal high-pass 'thump' filter had been removed. A pulsed Doppler system was then modified to produce five simultaneous outputs representing movement at depths separated by 1.5-cm intervals. These outputs represent the displacement inside tissue at the various depths. Signal processing was executed on a 32-bit computer with an analog-to-digital converter. On-line processing using a zero-crossing method and an off-line high-accuracy displacement estimation technique using an arc-tangent method were applied. Using computerized signal processing, it was possible to detect movements of a few hundred microns representing fetal breathing movements while rejecting gross movements due to maternal breathing, etc. Although further studies are required before clinical application, it appears that quantitative assessments of fetal breathing movements should be possible with this technique.

Journal Article↗

PubMedDate not supplied

Pulse glucometry: A new approach for noninvasive blood glucose measurement using instantaneous differential near-infrared spectrophotometry.

We describe a new optical method for noninvasive blood glucose (BGL) measurement. Optical methods are confounded by basal optical properties of tissues, especially water and other biochemical species, and by the very small glucose signal. We address these problems by using fast spectrophotometric analysis in a finger, deriving 100 transmittance spectra per second, to resolve optical spectra (900 to 1700 nm) of blood volume pulsations throughout the cardiac cycle. Difference spectra are calculated from the pulsatile signals, thereby eliminating the effects of bone, other tissues, and nonpulsatile blood. A partial least squares (PLS) model is used with the measured spectral data to predict BGL levels. Using glucose tolerance tests in 27 healthy volunteers, periodic optical measurements were made simultaneously with collection of blood samples for in vitro glucose analysis. Altogether, 603 paired data sets were obtained in all subjects and two-thirds of the data or of the subjects randomly selected were used for the PLS calibration model and the rest for the prediction. Bland-Altman and error-grid analyses of the predicted and measured BGL levels indicated clinically acceptable accuracy. We conclude that the new method, named pulse glucometry, has adequate performance for safe, noninvasive estimation of BGL.

Algorithms↗