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Biomedical subjects

H Kadono

Publications and source records attributed to H Kadono.

At least 19 recordsLinked to original sources
PubMed2003

Novel functional imaging technique from brain surface with optical coherence tomography enabling visualization of depth resolved functional structure in vivo.

Mapping of the activity of brain by optical intrinsic signal imaging (OISI) provides a two-dimensional activation pattern of visual cortical areas at a resolution of a few hundred microns. However, integration of the intrinsic signal over depth results in loss of finer information about functional organization across the depth. Here, we report the first successful implementation of optical coherence tomography (OCT) at around 30 microm depth resolution to investigate cortical functions of a cat brain in vivo. This technique, named functional OCT (fOCT) provided visually evoked changes in the OCT signal. The fOCT signal shows stimulus specificity that correlates well with that of the intrinsic signals and provides depth resolved layer specific functional information.

Animals↗
PubMed2001

Statistical interferometry based on a fully developed speckle field: an experimental demonstration with noise analysis.

A novel interferometric method named statistical interferometry is proposed and studied. In the method, in contrast to the conventional deterministic interferometry, the complete randomness of the two interfering light fields, i.e., the random interference of the fully developed speckle fields, plays an essential role and is used as a standard of phase in a statistical sense. Preliminary experiments were conducted to verify the validity of the method, followed by a computer simulation. As an experimental result, the accuracy of the measurements of an out-of-plane displacement was confirmed up to lambda/800 by comparison with the heterodyne interferometer. The method has the advantage of simplicity of the optical system required, while at the same time providing high accuracy.

Journal Article↗
PubMed1999

Inhibition of osteoblastic cell differentiation by lipopolysaccharide extract from Porphyromonas gingivalis.

Lipopolysaccharide from Porphyromonas gingivalis (P-LPS), an important pathogenic bacterium, is closely associated with inflammatory destruction of periodontal tissues. P-LPS induces the release of cytokines and local factors from inflammatory cells, stimulates osteoclastic-cell differentiation, and causes alveolar bone resorption. However, the effect of P-LPS on osteoblastic-cell differentiation remains unclear. In this study, we investigated the effect of P-LPS extract prepared by the hot-phenol-water method, on the differentiation of primary fetal rat calvaria (RC) cells, which contain a subpopulation of osteoprogenitor cells, into osteoblastic cells. P-LPS extract significantly inhibited bone nodule (BN) formation and the activity of alkaline phosphatase (ALPase), an osteoblastic marker, in a dose-dependent manner (0 to 100 ng of P-LPS extract per ml). P-LPS extract (100 ng/ml) significantly decreased BN formation to 27% of the control value and inhibited ALPase activity to approximately 60% of the control level on days 10 to 21 but did not affect RC cell proliferation and viability. P-LPS extract time-dependently suppressed the expression of ALPase mRNA, with an inhibitory pattern similar to that of enzyme activity. The expression of mRNAs for osteocalcin and osteopontin, matrix proteins related to bone metabolism, was markedly suppressed by P-LPS extract. Furthermore, P-LPS extract increased the expression of mRNAs for CD14, LPS receptor, and interleukin-1beta in RC cells. These results indicate that P-LPS inhibits osteoblastic-cell differentiation and suggest that LPS-induced bone resorption in periodontal disease may be mediated by effects on osteoblastic as well as osteoclastic cells.

Alkaline Phosphatase↗
PubMed1997

Inhibition of osteoblastic cell differentiation by conditioned medium derived from the human prostatic cancer cell line PC-3 in vitro.

Human prostatic carcinoma frequently metastasizes to bone tissue and activates bone metabolism, especially bone formation, at the site of metastasis. It has been reported that an extract of prostatic carcinoma and conditioned medium (CM) of a human prostatic carcinoma cell line, PC-3, established from a bone metastastic lesion, stimulate osteoblastic cell proliferation. However, there is little information about the effect of PC-3 CM on the differentiation of osteoblastic cells. In this study, we investigated the effect of PC-3 CM on the differentiation of two types of osteoblastic cells, primary fetal rat calvaria (RC) cells containing many undifferentiated osteoprogenitor cells, and ROS 17/2.8, a well-differentiated rat osteosarcoma cell line. PC-3 CM inhibited bone nodule formation and the activity of alkaline phosphatase (ALPase), an osteoblastic marker enzyme, on days 7, 14, and 21 (RC cells) or 3, 6, and 9 (ROS 17/2.8 cells) in a dose-dependent manner (5-30% CM). However, the CM did not affect cell proliferation or cell viability. PC-3 CM was found to markedly block the gene expression of ALPase and osteocalcin (OCN) mRNAs but had no effect on the mRNA expression of osteopontin (OPN), the latter two being noncollagenous proteins related to bone matrix mineralization. These findings suggest that PC-3 CM contains a factor that inhibits osteoblastic cell differentiation and that this factor may be involved in the process of bone metastasis from prostatic carcinoma.

Alkaline Phosphatase↗
PubMed1991

Formation of ion channels in planar lipid bilayer membranes by synthetic basic peptides.

We made use of a planar lipid bilayer system to examine the action of synthetic basic peptides which model the prepiece moiety of mitochondrial protein precursors and have antibacterial activity against Gram-positive bacteria. The sequences of the peptides used were as follows: Ac-(Ala-Arg-Leu)3-NHCH3 (3(3], Ac-(Leu-Ala-Arg-Leu)2-NHCH3 (4(2], Ac-(Leu-Ala-Arg-Leu)3-NHCH3 (4(3], Ac-(Leu-Leu-Ala-Arg-Leu)2-NHCH3 (5(2]. These peptides interacted differently with planar lipid bilayer membranes and membrane conductance increased by the formation of ion channels. The effects of the peptides on the macroscopic current-increase and on the probability of channel formation, at the single channel level were in the order of 4(3) greater than 4(2) approximately 5(2) much greater than 3(3), a finding which correlates with the antibacterial activity of these peptides. The micromolar (microM) order concentration at which the channel was formed resembles that causing antibacterial activity. Thus, the peptide antibacterial activity may occur through an increase in ion permeability of the bacterial membrane. The single-channel properties were investigated in detail using 4(3), the peptide with the highest ion channel-forming activity. Many types of channels were observed with respect to conductance (2-750 pS) and voltage dependency of gating. However, the channels were all cation-selective. These results suggest that the ion channels formed by peptide 4(3) may be able to take on a variety of conformations and/or assembly.

Amino Acid Sequence↗
PubMed1988

Effects of some psychotropic drugs on the b-wave of the electroretinogram in isolated rabbit retina.

The role of dopaminergic and cholinergic functions in the genesis of an electroretinogram is unclear. The present study was carried out to elucidate the direct actions of some psychotropic drugs in isolated rabbit retinas. Methamphetamine and apomorphine decreased dose-dependently the b-wave amplitude at a dose of 10(-7)-10(-5) g/ml. On the other hand, chlorpromazine and haloperidol, as well as atropine and amitriptyline, increased dose-dependently the b-wave amplitude at the same dose range. These data support the idea that dopaminergic and cholinergic systems play an important role in the genesis of the ERG.

Animals↗
PubMed1984

Body temperature changes in dogs exposed to varying effective temperatures.

Adult male and female Beagle dogs (eight total) were exposed individually, in series, to each of 23 effective temperatures for a period of 2 hours or until rectal temperature increased 1.1 degrees C. Rectal temperature was measured to the nearest 0.1 degree C by thermistor probes in the pre-test condition (basal temperature) and at each 5-minute interval during the test conditions (effective temperatures between 21.1 degrees C and 34.7 degrees C). The frequency at which dogs displayed a 1.1 degree C rise in rectal temperature was related to the magnitude of the effective temperature. At an effective temperature of 32.6 degrees C or greater, 100% of the dogs displayed a 1.1 degree C rise in rectal temperature. Between an effective temperature of 29.3 degrees C and 31.4 degrees C, some animals displayed a 1.1 degree C rise while others did not. At an effective temperature of 28.4 degrees C or below no animals displayed a 1.1 degree C rise. The mean time necessary for a 1.1 degree C rise was negatively correlated (P less than 0.01) to the magnitude of the effective temperature. The minimum effective temperature necessary to increase rectal temperature by 1.1 degree C in male Beagles (29.6 +/- 1.0 degree C) was not significantly different from females (30.8 +/- 0.4 degrees C).

Animals↗
PubMed1981

Body temperature, oviposition, and food intake in the hen during continuous light.

Deep-body temperature of the laying hen was measured with an implantable radio transmitter. Food and water intake and oviposition time were recorded, remotely, based on electric signals from microswitches attached to the individual cages. Body temperature and feeding activity of the laying hen under continuous light displayed a circadian rhythm. The length of the body-temperature cycle was 25.2 h, and the feeding cycle was 25.3 h. These values appear to be associated with the animal's laying cycle which was 25.3 h. The laying cycle of the hen can play an important role in the maintenance of circadian rhythms of body temperature and feeding activity. Both the marked temperature rise found at the time of oviposition and the prelaying (or nesting) behavior may be controlled by a preovulatory surge of luteinizing hormone (LH) and progesterone.

Animals↗
PubMed1978

Telemetry measured body temperature of domestic fowl at various ambient temperatures.

Adult, male Single Comb White Leghorn chickens (SCWL) were housed unrestrained in individual cages in a controlled environment room with a photoperiod of 12L:12D. By means of surgically implanted radio transmitter, body temperatures were recorded hourly for five consecutive days at each of six experimental temperatures: 23, 26, 29, 32, 35, and 38 C. The data were evaluated statistically by correlogram, periodogram, and harmonic analysis. Period length of each cycle was about 24 hr at all ambient temperatures. No significant differences in deep body temperature were observed until the ambient temperature reached 32 C; but highly significant increases were detected between 32, 35, and 38 C. Diurnal differences in body temperature ranged from .6 to 1.1 C. It has been suggested that the body temperature of male chicken may be under the control of a biological clock that synchronizes with the solar day.

Animals↗