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Biomedical subjects

M O Yamada

Publications and source records attributed to M O Yamada.

At least 19 recordsLinked to original sources
PubMed2001

Selective accumulations of aluminum in five human arteries.

The aim of the present study was to determine variability of aluminum (Al) accumulation in human arteries and to observe the relationship between Al and five other elements (Ca, Fe, Mg, P, and Si) in the arteries. The Al contents in the thoracic aorta, basilar, coronary, femoral, and radial arteries of 26 human subjects were estimated by an inductively coupled plasma-atomic emission spectrometer and compared quantitatively to five elements. Al was detected in 88% of the cases in both the femoral and radial arteries, 73% in the coronary artery, 58% in the aorta, and 31% in the basilar artery. The average Al content was highest in the femoral artery (48.3 +/- 15.0 microg/g dry weight) and lowest in the basilar artery (8.1 +/- 3.6 microg/g). The Al had positive correlations with P, Ca, or Mg in both the aorta and femoral artery, and with Ca or P in the basilar artery. In the coronary artery, a correlation was found between Al and Si. No relationships were found between Al and each of the five elements in the radial artery. From these results, Al varied widely among the five arteries and accumulated more in the femoral and radial arteries but less in the basilar artery. These accumulations of Al were positively correlated with Ca or P in several arteries, but not sufficiently to explain the accumulation of Al. Further investigations are required to understand the mechanism of the variability of Al accumulation in the arteries.

Aged↗
PubMed2001

Calcium and phosphorus in aged human cerebral arteries.

To elucidate the compositional changes of the cerebral arteries with aging, the authors investigated age-related changes of the calcium and phosphorus contents in the cerebral arteries by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of 11 men and 5 women, ranging in age from 52 to 96 yr. The anterior, middle, and posterior cerebral arteries derived from the same subjects were used in the present study. It was found that there were no significant relationships between age and calcium or phosphorus content in the anterior, middle, and posterior cerebral arteries, indicating that the accumulation of calcium and phosphorus scarcely occurred in the anterior, middle, and posterior cerebral arteries with aging. It was examined whether there were relationships in the calcium and phosphorus contents among the anterior, middle, and posterior cerebral arteries, It was found that there was a significant relationship in both the contents of calcium and phosphorus between the middle and posterior cerebral arteries, but not between the anterior and middle cerebral arteries nor between the anterior and posterior cerebral arteries.

Age Factors↗
PubMed2000

Age-related changes of elements in human ureter.

To elucidate changes of the ureter with aging, the authors investigated age-related changes of element contents in human ureters. The subjects consisted of seven men and seven women, ranging in age from 61 to 97 yr. The contents of calcium, sulfur, and iron in the ureters increased progressively with aging, whereas the contents of phosphorus and magnesium did not increase with aging. Significant relationships were found both between calcium and sulfur contents and between calcium and iron contents in the ureters, but not between calcium and either phosphorus or magnesium contents. It was noteworthy that a significant relationship was also found between sulfur and iron contents in the ureters. It remains uncertain whether calcium forms a compound with sulfur or iron in aged human ureters or not.

Aged↗
PubMed2000

Accumulation of calcium and phosphorus in the mitral valve in comparison with the abdominal aorta and the scaphoid bone.

To clarify why calcification of the mitral valve occurred, the authors chose the abdominal aorta and the scaphoid bone among many arteries and bones, and they studied both relationships in element contents between the mitral valve and the abdominal aorta and between the mitral valve and the scaphoid bone. The subjects consisted of 11 men and 8 women, ranging in age from 52 to 96 yr. The accumulation of calcium and phosphorus occurred progressively with aging in the mitral valve, whereas it became the highest in the sixties in the abdominal aorta and did not increase thereafter. The accumulation of calcium and phosphorus occurred in the abdominal aorta earlier than the thoracic aorta, in which it became remarkable in the seventies. It should be noted that in regard to the accumulation of calcium and phosphorus, no significant correlations were found between the mitral valve and the abdominal aorta. It is suggested that calcification of the abdominal aorta is not essentially accompanied by calcification of the mitral valve. The scaphoid bone was chosen among many bones consisting mainly of spongy bone and the relationship was examined between the calcium content in the mitral valve and the bone mineral density of the scaphoid bone. It was found that there was a low relationship between them. Therefore, it is suggested that a part of the surplus calcium released from bones is deposited in the mitral valve.

Aged↗
PubMed2000

Age-related variations of elements as compared among optic, radial, and sciatic nerves.

To elucidate changes of peripheral nerves with aging, the authors studied age-related changes of element contents in the optic, radial, and sciatic nerves by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of seven men and seven women, ranging in age from 61 to 97 yr. The contents of phosphorus and sulfur remained constant through ages 61 to 97 yr in three nerves, the optic, radial, and sciatic nerves. It was found that there were age-related differences in calcium content among the optic, radial, and sciatic nerves: The calcium content of the optic nerve increased progressively with aging; in the radial nerve, it was hardly changed with aging; in contrast, the calcium content of the sciatic nerve decreased gradually with aging. In addition, it was found that in the radial nerve there were moderate correlations between age and zinc or sodium content, whereas significant correlations between age and the content of silicon or iron were found in the sciatic nerve. Furthermore, there was a correlation between the silicon and iron contents in the sciatic nerves.

Aged↗
PubMed2000

Age-dependent changes of elements in human trachea.

To elucidate compositional changes of human trachea by aging, element contents in tracheae were determined by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of seven men and seven women, ranging in age from 61 to 97 yr. The sulfur content of the tracheae decreased gradually with aging. In regard to calcium and phosphorus, both the contents increased to about threefold amounts in their seventies compared with those in their sixties, and decreased thereafter. The contents of calcium and phosphorus were the highest in their seventies. Therefore, it is likely that surplus calcium released from bones is deposited temporally in the trachea, and the deposits are released from the trachea at older age. Based on our results of human cartilages, there are two types in regard to calcium accumulation: The first type is that calcium accumulation occurs progressively with aging; the second one is that calcium accumulation becomes the highest in the seventies or eighties, and decreases thereafter. Therefore, the trachea belongs to the second type. Furthermore, the magnesium content remained constant through the age range.

Aged↗
PubMed2000

Possible contaminant origins of the red cosmetics decorating ancient burial sites in Japan.

Marker elements were estimated from the red cosmetics collected from different ancient burials and mine ruins in three separate districts of Japan. Element levels were displayed in reference to the relative amount to sulfur (RA/S), by which the cosmetics were divided into five types: I--a low Hg/S with a low Fe/S; II--both moderate Hg/S and Fe/S; III--a moderate Hg/S with a high Fe/S; III 2--a high Hg/S with a moderate Fe/S; IV--a high Hg/S with a high Fe/S. The cosmetics can be further characterized by referring to other contaminants such as Zn, Cu, and Mn. These combined analyses with contaminant metals were capable of characterizing the origins of the cosmetics; it is useful to compare them to each other. The cosmetics were identified as being due to several groups of contaminants from ancient mines in Japan, and also with this system analysis of the markers it is possible to identify them from neighboring countries.

Archaeology↗
PubMed1999

High accumulation of calcium and phosphorus in human iliac arteries.

To elucidate accumulation of minerals in human iliac arteries with aging, the content of minerals was analyzed by inductively coupled plasma atomic emission spectrometry. Bilateral common, internal, and external iliac arteries of 16 men and 8 women, ranging ages from 65 to 93 yr, were examined. It was found that an extremely high accumulation of calcium and phosphorus occurred in the common iliac artery at old age, being higher than that of the internal and external iliac arteries. It should be noted that the accumulation of calcium and phosphorus is the highest in the common iliac artery among the human arteries examined to date. Regarding sexual differences, the content of calcium and phosphorus in the common and internal iliac arteries was higher in women than in men, whereas their content in the external iliac artery was lower in women than in men.

Aged↗
PubMed1998

Age-related changes of mineral contents in the human aorta and internal thoracic artery.

To elucidate accumulations of minerals in the human aorta and internal thoracic artery, their relative contents (RCs) of minerals were analyzed by inductively coupled plasma atomic emission spectrometry. Aortas from 47 men and 24 women subjects were examined. The ages of these subjects ranged from newborn to 99 yr. After the age of 40 yr, RCs of calcium and phosphorus began to increase, and thereafter increased stepwise in the 50s and 70s. In the 70s, their accumulations were markedly increased. Internal thoracic arteries from 16 men and 7 women subjects were examined. These subjects ranged in age from 65-93 yr. It was found that all the RCs of calcium were low, <5.0 mg/g dry wt, and there was no age-dependent increase of calcium contents in internal thoracic arteries.

Adolescent↗
PubMed1997

Trace element composition and histological analysis of rat bones from the space shuttle.

The physiological and pharmacobiological changes associated with space flight are of greater concern. Exposure to a weightless environment has been shown to have numerous effects on body composition and organ functions. Alterations include decreases in muscle and liver mass, changes in bone structure and integrity, and changes in cardiovascular functions. Zero-gravity in particular has been reported to inhibit several physiological processes of bone formation, retard bone growth and impair the mechanical properties of bones. This report examines the effect of 14 days of spaceflight on the bone trace element compositions of rapidly growing rats. Marked changes of bone trace element contents were found in either weight-bearing bones or non-weight-bearing bones, depending on the metal species. Histological examination revealed an irregular thickening of the endosteal surface of the cortical bone (thoracic vertebrae) of the in-flight rat, whereas it was uniform in the ground control. We suggest that the microgravity environment causes several bone alternations, such as abnormal trace element compositions and defects in vertebral maturation.

Animals↗
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↗
PubMed1987

Topogenesis of glycogen distribution pattern in post-natal rat liver in reference to the activity-rest cycle.

The present study, on immature rats, revealed that in the liver with exclusively diploid cell population (MD), the glycogen content was half of the adult level and the 24 h distribution pattern was reverse, i.e. highest in the evening and lowest in the morning. In these animals, in general, the protein content was high and did not show any circadian rhythm but incidentally showed a time dependent zonal distribution pattern. The low glucose-6-phosphatase activity reciprocates with low glycogen content. The relative number of cells per unit area showed a time dependent distribution pattern. The liver with equal distribution of diploid and tetraploid classes (MD:MT), attained the classical circadian rhythm of glycogen with high morning and low evening oscillation pattern. The TRIDENT measurements manifest the zonal distribution pattern with high values at the perilobular region (PL) and low at the centrolobular region (CL). The relative cell number study along the acinus demonstrated more number of cells around the PL region than that at CL region, indicating a variation in the cell size. Eventually, the protein content showed a circadian rhythm in this group, with high amount in the morning. The zonal distribution pattern always revealed the high content near the perilobular region. This could be due to more number of cells per unit area in this region. The glucose-6-phosphatase showed a circadian rhythm. The typical high glucose-6-phosphatase in the perilobular region could be further subzonated into small groups of high activity surrounded by lighter zones, thus establishing the heterogeneous function of liver parenchymal cells.

Animals↗
PubMed1981

A cyst-forming Eimeriina found in the kangaroo imported from Australia.

One pair of grey kangaroos was imported from Australia in July 1974. One month after arrival they successively died of serious intestinal bleeding. On biopsy, the epithelium was destroyed and replaced with necrotic degeneration with numerous dot-like flecks of bleeding from the stomach till the jejunum. On histopathological examinations, the epithelium was composed of swollen glandular cells which form giant cells with eccentrically displaced nuclei. The cell forms a cyst which develops solitarily and gathers together to form a racemous shape. These cysts are bound to the thick wall and the parasites are found in the vesicular space. Several sequences of the parasite growth are demonstrated. The parasites migrated initially into the cytoplasm and then to the nucleus of the glandular cell in which they grow, then the cyst is formed and finally the parasites flow out to penetrate again into normal cells. The parasite cell changes to crescent- or spindle-shape as a tachyzoite. The relative nucleic acid content of the parasite in the host cell or its nucleus is measured by spectrophotometry and fluorometry. The data suggest that the parasites are reproduced in intestinal glandular cells of the kangaroo.

Animals↗