Masayo Ichii

Age-related change of mineral content in the human thoracic aorta and in the human cerebral artery

The relative contents (RCs) of mineral elements in aortae and cerebral arteries from 23 subjects, with ages ranging between 45 and 99 yr, were analyzed by inductively coupled plasma atomic emission spectrometry. The RCs of calcium, phosphorus, and magnesium in the aortae increased markedly after the age of 70. While the RC of sulfur in aortae decreased gradually after that age. It was found that accumulation of calcium and phosphorus occurred primarily in the tunica media of aorta, and secondarily in the tunica intima. Furthermore, the RCs of calcium, phosphorus, and magnesium in cerebral arteries increased markedly after the age of 70, whereas the RC of sulfur in cerebral arteries decreased after age 70. It was found that accumulation of calcium and phosphorus in the cerebral arteries were 30 and 60%, respectively, lower than those in the aortae with ages ranging between 45 and 99 yr.

DIFFERENCE OF MINERAL CONTENTS IN HUMAN INTERVERTEBRAL DISKS AND ITS AGE-RELATED CHANGE

To establish a difference of the relative contents (RCs) of elements among the cervical, thoracic, and lumbar intervertebral disks and its age-related change, the intervertebral disks between the axis and the sacrum, which were resected from the nine cadavers who died at 53 to 99 yr old, were analyzed by inductively coupled atomic plasma emission spectrometry. It was found that both the RCs of calcium and phosphorus were high in the cervical disks, especially the highest in the disk between the 6th and 7th cervical vertebrae, and lower in the order of the cervical, thoracic, and lumbar intervertebral disks. In regard to the RCs of sulfur and magnesium, there were no significant differences among the cervical, thoracic, and lumbar intervertebral disks. In addition, it was found that both the RCs of calcium and phosphorus in the cervical intervertebral disks started to increase in the sixth decade of life, became the highest in the eighth decade of life, and then decreased.

Comparison of three different methods for measurement of tissue platinum level

We attempted to make a comparison of three methods for tissue platinum; atomic absorption spectrometry (AAS), inductively coupled plasma atomic emission spectrometry (ICP-AES), and inductively coupled plasma mass spectrometry (ICP-MS). The determination lim its were 0.05 ng/mL on ICP-MS, 50 ng/mL on ICP-AES, and 200 ngJmL on AAS, and the recovery rates were 97.7 ± 6.9% on ICP-MS, 69.0 ± 3.0% on ICP-AES, and 102.4 ± 4.0% on AAS, respectively. Plat inum was detected by ICP-AES and ICP-MS in human vertebrae, but the level was higher by ICP-AES than by ICP-MS. In the mouse kid ney treated with cisplatin, platinum was detected by ICP-MS, but not by ICP-AES. As cadmium gives the absorption peak close to plat inum, cadmium was measured together with platinum by ICP-AES in the vertebrae. From these, ICP-MS is the most sensitive for measure ment at tissue platinum. The sensitivity of ICP-AES looks worse for measuring the tissue platinum, and it is necessary to take care of the contaminant of metals, especially cadmium. AAS is not suitable for measurement of tissue platinum as in the vertebrae and kidneys, because platinum was not detectable by AAS.

Age-independent constancy of mineral contents in human vertebra and auditory ossicle.

To elucidate age-related changes of mineral contents in human bones, element contents of human vertebrae and auditory ossicles were determined by inductively coupled plasma atomic-emission spectrometry. The cervical, thoracic, and lumbar vertebrae were removed from 12 vertebral columns. The mallei of auditory ossicle were removed from 27 cadavers.It was found that average relative contents (RCs) of calcium and phosphorus in cervical, thoracic, and lumbar vertebrae remained almost constant within ages ranging from 46 to 99 y. In addition, it was found that the RCs of calcium and phosphorus in men’s and women’s mallei remained constant within ages ranging from 40 to 98 yr. These results support the view that there is no significant agedependent change of mineral contents in human bones.

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.

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 withcis-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 μg/g dry tissue in the intervertebral discs and 0.60–1.28 μg/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.

Detection of Platinum in the Brain of Mice Treated with Cisplatin and Subjected to Short-term Hypoxia

Cisplatin is widely used for cancer treatment but has strong side‐effects, including nephrotoxicity. Neurotoxicity has been thought to be limited to peripheral damage because the blood‐brain barrier is thought to be impervious to hydrophilic substances such as cisplatin. Because anoxic ischaemia has been associated with lesions of the barrier, inductively coupled plasma mass spectrometry has been used to monitor the accumulation of platinum in the brains of mice treated with cisplatin and exposed to oxygen‐deficient atmospheres.

Free Radical Scavengers Suppress the Accumulation of Platinum in the Cerebral Cortex

We investigated whether free radical scavengers and antioxidants inhibit the accumulation of platinum (Pt) in the cerebral cortex. Pt was detected in the cerebral cortex of mice afters administration of cisplatin and exposure to short-term hypoxia. When mice were treated with either allopurinol (20 mg/kg) or catalase (100 mg/kg) before cisplatin administration and low oxygen exposure, Pt was not detected in the cerebral cortex. However, Pt was detected in the cerebral cortex of mice pretreated with either a low dosage of allopurinol or heat-denatured catalase. Furthermore, Pt was detected in the cerebral cortex of mice preadministered vitamin C, vitamin E, or deferoxamine. Lipid peroxide levels in the cerebral cortex increased 10 min after the treatment of hypoxia, and peaked 30 min after the treatment. These results suggested that short-term hypoxia produces free radicals, which allows Pt to pass through the blood-brain barrier and accumulate in the cerebral cortex, and that the production of free radicals is reduced by the administration of either allopurinol or catalase, which prevents Pt from passing through the barrier.

AN IMPROVED METHOD FOR ESTIMATING ORIGINAL MINERAL CONTENTS IN EXCAVATED BONE USING SULFUR

Trace element analysis in excavated bones is complicated by the lack of a reliable index for estimating the original amount of bone material. In this study, we subjected modern human bones to alkali treatment to simulate aging. Alkali treatment of vertebrae with attached muscle did not affect sulfur (S) content; it increased the magnesium (Mg), phosphorus (P), and zinc (Zn) contents, and tended to decrease iron (Fe) content of the bones. When vertebrae cleaned of muscle were used, alkali treatment did not affect S and Fe contents but increased Mg, P, Ca, and Zn contents Ca and S contents were higher in excavated bones (200–1300 yr old) than in their surrounding soils. In contrast, S, Mg, and Ca contents per dry weight did not differ between the excavated bones and the alkali-treated modern bones. These results indicate that S can provide a more accurate index of excavated bones than the often-used Ca content or dry wt measures, especially for bones excavated from calcium-rich soils.

Renal Changes of Streptozotocin-Induced Diabetic Rats Fed a Low-Zinc Diet

The changes in kidneys of streptozotocin (STZ)-induced diabetic rats fed a low-zinc (LZ) diet were observed. Calcium deposits were detected in the LZ-diabetic groups from the 2nd to the 8th week. The deposits were mainly detected in the corticomedullary junction, and found in the tubular lumina and epithelial cytoplasm and interstitium. Tubular morphological changes, including luminary distension, epithelial flattening, and paleness of cytoplasm and nuclei, were observed near the calcium deposits in the LZ-diabetic group over the 2nd week. Moreover, at the 8th week, wedge-shaped vasogenic lesions were found on the surface of the renal cortex in the LZ-diabetic group. No changes were detected in the control for the LZ or in the diabetic group fed a standard (SC) diet. When STZ was administered, plasma glucose level in groups fed LZ or SC diet increased in the 1st week, and over the 2nd week, glucose level was maintained at more than 400 mg/dL. Glucose level of the LZ-diabetic group did not differ from that of the SC-diabetic group. However, urinary N-acetyl-beta-D-glucosaminidase activity of the LZ-diabetic group at the 8th week was significantly higher than that of the SC-diabetic group. These findings suggested that low-zinc diet hastens renal damages in diabetic rats.