Biomedical subjects

Y Tohno

Publications and source records attributed to Y Tohno.

At least 73 records · Page 4Linked to original sources

PubMed1996

Age dependency of nanosecond fluorescence characteristics in human arteries.

Human arteries fluoresce as a result of illumination by UV-light. The fluorescence characteristics of the human aorta and basilar artery were investigated with respect to aging. For this experiment, a time-resolved microscope fluorometer was employed. Resultant fluorescence decayed on a nanosecond scale when applying pulse UV-light. These fluorescences were found to be age dependent in the basilar artery; the fluorescence decay time decreased with increasing human age. However, fluorescence from the aorta did not show the age dependency.

Age Factors↗

PubMed1996

Bindings of metallothionein to supranucleosomal fibers in mouse pancreatic nuclei after induction by 4-aminopyrazolo [3,4-D] pyrimidine.

To examine intranuclear localization of metallothionein (MT) induced by administration of 4-aminopyrazolo [3,4-d] pyrimidine (4-APP), the present study of MT was performed by immuno-electron microscopy. One day after oral administration of 4-APP, the mouse pancreas removed and frozen with dry ice was cut at about 1 mm thickness. Pancreatic slices were reacted with anti-MT antibody, fixed with formaldehyde and glutaraldehyde, and embedded in hydrophilic Lowicryl K4M resin. Ultrathin sections were reacted with the secondary antibody labelled with colloidal gold, and stained both with uranyl acetate and with lead citrate. It was found that the MT site was shown simultaneously in the chromatin and in the rough endoplasmic reticulum of mouse pancreatic exocrine cells one day after administration of 4-APP. The structure of MT-binding chromatin was composed of supranucleosomal fibers, but not of nucleosomal fibers.

Adenine↗

PubMed1995

Accumulation of mercury in excavated bones of two natives in Japan.

Mercury content of excavated bones and surrounding soil was compared between the two areas of Shikoku, Tokushima and Matsuyama. Results show a high variance of mercury content between localities and between ages of the burials. There was a high mercury occurrence in the 6-7th century in Tokushima and a moderate one in Matsuyama, and a trace in the 12-17th century in both places. Moreover, a low level of mercury was observed in the soil samples of Tokushima, and mercury was not detected in any of the Matsuyama soil samples. Therefore, these occasions of high mercury content may be due to artificial uptake, and may relate to differences in conventions and customs.

Bone and Bones↗

PubMed1995

Chromatin loop size in human leukemia (HL-60) cells.

Human leukemia (HL-60) cells were treated with 0.1% detergent Joy and chromatin, protruded from the cell, was observed with an electron microscope. It was demonstrated that most, but not all of the protruded chromatin fibers had a loop structure. The average length of the protrusions of chromatin from the nucleus was 8.47 microns. A high magnification revealed that most of the protruded chromatin consisted of beaded nucleosomal fibers. Therefore, the chromatin loop size was estimated to be 315 +/- 47 k base pairs in length. This length is much longer than that of the fragmented DNA seen in the apoptosis of HL-60 cell, conflicting with the hypothesis that the DNA fragmentation is related to the size of the chromatin loop.

Chromatin↗

PubMed1995

Anomaly of the ulnar artery arising from the brachial artery.

A high origin of the ulnar artery was encountered in the body of an 87-year-old Japanese man in the course of normal anatomic dissection at Nara Medical University. The left ulnar artery originated from the brachial artery at the height of the left inferior angle of the left scapula and passed medially to the brachial artery and the median nerve. In the forearm, the ulnar artery passed deep to the flexor carpi ulnaris muscle. Thereafter, the two branches from the ulnar artery contributed to form the superficial and deep palmar arterial arches. The left brachial artery was divided into two terminal branches of the radial and common interosseous arteries.

Aged↗

PubMed1995

Inhibition and down-regulation of poly(ADP-ribose) polymerase results in a marked resistance of HL-60 cells to various apoptosis-inducers.

In a previous report we described that adenosine-induced apoptosis of HL-60 cells was blocked by the pretreatment of cells with a potent inhibitor (3-aminobenzamide) of poly(ADP-ribose) polymerase (PARP). The pretreatment of the cells with nicotinamide, another inhibitor of the enzyme, also suppressed most effectively the adenosine-induced apoptosis. This inhibition was reversible and observed during apoptosis mediated by other known apoptosis inducers such as actinomycin D and staurosporine (group I inducers), but nicotinamide was ineffective on the apoptosis mediated by VM 26, camptothecin and A23187 (group II inhibitors). In addition to the enzyme inhibition, a down-regulation of the enzyme level caused by the pretreatments of cells with differentiation-inducing agents, retinoic acid (RA) and dimethylsulfoxide (DMSO) also resulted in a marked resistance of the cells to the apoptosis inducers. A pretreatment of the cells for a limited time of 24 hrs. by these agents decreased the PARP level to 66-75% of the untreated cells and the cells showed a quite similar resistance to the group I apoptosis inducers like the cells treated with the enzyme inhibitors, whereas they were still sensitive to the group II inhibitors. A more prolonged treatment for 48 hrs. of the cells with RA and DMSO resulted in further down-regulation of the cellular PARP reaching respectively 50 and 43% of control cells and at this stage, the cells became resistant to all the inducers of both groups. These results suggest that the pathway, by which both groups of the inducers initiate and progress apoptosis, is not identical but include at least two different processes which are differently affected by PARP-inhibition or by different levels of cellular PARP.

Adenosine↗

PubMed1994

Accumulation of platinum in the intervertebral discs and vertebrae of ovarian tumor-bearing patients treated with cisplatin.

Platinum was determined by the inductively coupled plasma mass spectrometry (ICP-MS) in the intervertebral discs and vertebrae of ovarian tumor bearing patients treated with cis-diamminedichloro-platinum (II) (cisplatin). Platinum was 0.05 ng/mL at the absolute detection limit, and platinum was undetectable in the intervertebral discs and vertebrae of human specimens without cisplatin treatments. On the other hand, platinum was detected in the intervertebral discs and vertebrae of patients administered cisplatin, and platinum concentration was at levels of 1.06-10.31 micrograms/g dry tissue in the intervertebral discs and 0.60-1.28 micrograms/g dry tissue in the vertebrae, respectively. The platinum level of intervertebral discs was 4.3-fold higher than that of the vertebrae. Thus, platinum accumulates greatly in the intervertebral discs and somewhat in the vertebrae after administering cisplatin to patients for therapy.

Adenocarcinoma↗

PubMed1994

Gradient of mineral contents of vertebral column with special reference to intervertebral discs.

To study quantitatively the mineral elements in the vertebral column, we examined the vertebrae and intervertebral discs resected from three normal cadavers which died at middle age, by inductively coupled plasma atomic emission spectrometry. The relative contents of calcium, phosphorus, and sodium in vertebrae were high in the order from cervical to lumbar vertebrae. The ratios of calcium per phosphorus were 1.80 +/- 0.25 in cervical vertebrae, 1.59 +/- 0.22 in thoracic vertebrae, and 1.23 +/- 0.24 in lumbar vertebrae. The ratio of cervical vertebrae was the highest among them. In regard to intervertebral discs, both the relative contents of calcium and phosphorus were very much higher in the intervertebral discs between the 4th and 8th thoracic vertebrae than the others.

Bone Density↗

PubMed1993

Anomaly of bilateral persistent sciatic arteries.

A pair of persistent sciatic arteries was encountered in the body of a 91-year-old Japanese woman in the course of an ordinary dissection at Nara Medical University. The artery of each side followed nearly the same course in the posterior aspect of the thigh; after leaving the pelvis through the infrapiriform foramen, the persistent sciatic artery was observed descending between the tibial and common peroneal nerves, accompanied by the sciatic vein. In the popliteal fossa, the persistent sciatic artery ended by joining the popliteal artery. The sciatic nerves on both sides were found to have divided, while in the pelvis, into the tibial and the common peroneal nerves; the former passed through the infrapiriform foramen, while the latter perforated the piriformis muscle to reach the posterior aspect of the upper thigh.

Aged↗

PubMed1993

A possible association of nuclear lamina with chromatin.

The nuclear lamina associated with chromatin was examined by electron microscopy. Nuclei isolated from rat ascites hepatoma cells were swollen in 0.2 mM EDTA (pH 7.0) and broken by a homogenizer. The resulting nuclear fragments were dialyzed against 0.2 mM EDTA (pH 7.0) overnight, fixed in formalin and sedimented on grids by centrifugation, then stained with 2% uranyl acetate and rotary-shadowed with platinum-palladium. The nuclear lamina consists of two filaments, twisting together both the filaments associated with chromatin fiber. The single filament of nuclear lamina of about 31 nm in width forms certain rings of about 187 nm in diameter, taking a distance of about 0.37 micron in length between the neighbouring rings. Thus, the arrangement of rings was proposed a packing structure in conforming the nuclear laminar complex with chromatin.

Animals↗

PubMed1990

Deduction of DNA from artificial aggregates of erythrocyte nucleosomes.

The nucleosomal aggregates were obtained by micrococcal nuclease treatment to chicken erythrocyte nuclei. There still leaves a bulk of nucleosomes. We used two different DNA assay methods to determine DNA in in situ nucleosomes; the Feulgen DNA assay which shows a positive apurinic acid, and the fluorometry with Hoechst 33258 which reveals only intact AT base pairs. On applying those methods to the aggregates, even in a short digestion, Feulgen DNA remains only about 1/4 of the non-digested nuclei and the fluoroassay leaves only a trace amount of AT base pairs. Thus, the nucleosomes derived from the heterochromatin of erythrocytes are not preserved as the residual DNA of Feulgen hydrolysis. This also suggests that the bulk of nucleosomal DNA is masked and sensitive to neither the Feulgen assay nor the fluorometry of AT base pairs.

Animals↗

PubMed1989

[A case of the thyroidea ima artery arising from the aortic arch].

The present report describes a case of the thyroidea ima artery observed in a 65-year-old Japanese male on dissection in 1988. The thyroidea ima artery arose from the aortic arch between the branchiocephalic trunk and the left common carotid artery. The thyroidea ima passed to the left lobe and isthmus of the thyroid gland for the supply of these. The inferior thyroid artery on the right side was of common type in its origin and course, though that on the left side was absent. Either of the superior thyroid arteries arose from the common carotid artery.

Aged↗

PubMed1989

Electron microscopic studies on chromatin loop of rat ascites hepatoma cells.

Isolated nuclei from rat ascites hepatoma cells were treated with 0.09% detergent Joy and chromatin, protruded from the nucleus, was observed with an electron microscope. It was demonstrated that most, but not all of the protruded chromatin fibers had a loop structure. The protrusion of chromatin from the nucleus was 3 microns in average length. A high magnification view showed that the protruded chromatin consisted mainly of beaded nucleosomal fiber. Therefore, the chromatin loop size at the level of nucleosomal fiber was estimated to be at least 6 microns in length.

Animals↗

PubMed1985