Shiro Iwata

Studies on Amyotrophic Lateral Sclerosis by Neutron Activation Analysis-2. Comparative Study of Analytical Results on Guam PD, Japanese ALS and Alzheimer Disease Cases

Abstract: Metal analysis of calcium, manganese, aluminum and copper in CNS tissue samples of degenerative CNS disease cases (six Japanese ALS, three Japanese Alzheimer disease, four Guam PD, one Guam ALS) using neutron activation analysis, was conducted with following results: Five of six Japanese ALS cases, two of three Japanese Alzheimer disease cases and all of four Guam PD cases showed a high content of calcium and aluminum in CNS tissue with a significant positive correlation between calcium and aluminum and/or between calcium and manganese.

Studies on amyotrophic lateral sclerosis by neutron activation analysis.

Content of calcium, manganese and aluminum in CNS tissue was measured by neutron activation analysis in four ALS and three control cases with the following results:

The Half Life of Tb

A sample of Gd/sub 2/O/sub 3/ was borabarded for four hours with 38.5- Mev alpha particles and the activity of Dy/sup 157/ produced by the ( alpha ,3n) reaction was separated from the target material. Terbium was separated from dysprosium by an ionexchange method. The decay rate of Tb/sup 157/ nuclei was determined from the counting rate of the K x rays in a well type crystal, and the K and L electron capture ratio was measured using a NaI(Tl) crystal covered with Al, corrected for absorption by the Al cover, self absorption, photopeak efficiency, and fluorescence yield. The half life of Tb/sup 157/ was estimated at 160 ction in DDT-C/ 40 yr; a decay mode was proposed. (C.E.S.)

Decay of 150Eu

Abstract Carrier free sources of 150Eu were prepared from bombardment of enriched 150Sm with 11 MeV deuterons and 9 MeV protons. The half-life was determined to be 12.79±0.08 h. The maximum energy of the negatons was 1.02±0.01 MeV and the Kurie plot showed almost an allowed shape. However, the experimental shape factor showed a slight deviation from the allowed one. This decay was estimated to be 0− or 1− to 0+ transition. Positons with a maximum energy of 1.8±0.3 MeV and an intensity of about 0.3% and the K X-ray following orbital electron capture with an intensity of 3.9±0.2% were found. In scintillation measurements 15 gamma rays were observed. Gamma gamma coincidence studies were performed at several gate windows for gamma rays and annihilation radiations. The decay scheme of 150Eu was constructed on the basis of these results.

Studies on Amyotrophic Lateral Sclerosis by Neutron Activation Analysis–3. Systematic Analysis of Metals on Guamanian ALS and PD Cases

Abstract: Central nervous system tissue autopsy samples from seven Guam amyotrophic lateral sclerosis, four Guam Parkinsonism‐dementia complex and three Chamorro control cases were analyzed for aluminum, calcium, copper and manganese contents using the neutron activation analysis. ALS cases showed a high content of aluminum which corresponded to the area of degeneration in CNS tissue while calcium and manganese each showed a low content. PD cases showed a still higher content of aluminum, diffusely distributed. Copper and manganese levels were high while calcium showed a low content. The low calcium contents may be ascribed to the long period of formalin fixation. These findings support the indication that aluminum may participate in a CNS degenerative process of these diseases with interaction of other metals.

Study of the effects of environmental factors on the local incidence of amyotrophic lateral sclerosis.

Abstract The etiology of amyotrophic lateral sclerosis has remained unknown since the disease was first described by Charcot and Joffroy in 1869. Although extensive epidemiological and genetic studies were carried out in the past several years in the Kii Peninsula of Japan as well as on Guam in the Mariana Islands, these studies did not allow a determination of what environmental factors induced the disease, and conclusive genetic factors have not emerged. In a search for possible etiological factors in the environment, the role of heavy metals is considered because a possible concentration of amyotrophic lateral sclerosis and Parkinsonism-dementia among former manganese miners on the Island of Guam was suggested in 1964. Previous chemical analyses of trace metals in human nervous system tissue and in environmental samples of river and drinking water, soil, plants, and fish provided no remarkable findings, because of the very small amounts of heavy metal ions in the human nervous system and because of the complicated chemical behavior of the metal ions in the environment. Then a further highly sensitive analysis by the neutron activation method was undertaken on materials from the Kii Peninsula in Japan and from Guam, both areas having a high incidence of motor neuron disease. The results show that, on Guam, the samples of river and drinking water have quite a high content of manganese; however, in Japan, factors of manganese encephalopathogeny are not observed and, rather, the low content of calcium and magnesium ions in water may play an important role in the cause of the disease.

Decay of 157Tb

A sample of Gd2O3 enriched to 97.01% in the mass number 156 was bombarded with 38.5 MeV alpha-particles. The activity of 157Dy produced by the (α, 3n) reaction was isolated chemically from the target material. The number of nuclei of 157Dy was determined from the counting rate on the 330 keV photopeak. After the 157Dy radioactivity (T12 = 8.2 h) had died out, terbium was separated from dysprosium. The scintillation spectrum of the terbium fraction showed only one photopeak at the energy of 43 keV X-rays of gadolinium when the source was situated inside a well-type crystal. The number of 157Tb nuclei was determined from the counting rate of the K X-rays in the well-type crystal and by the measurement of the K and L orbital electron capture ratio with a thin NaI(Tl) crystal. From the number of nuclei of the parent and the daughter, the half life of 157Tb was estimated to be 150±30 y. A decay scheme of 157Tb is proposed.

Neutron Activation Analysis of Calcium in Central Nervous System Tissue of Amyotrophic Lateral Sclerosis Cases

Content of calcium in CNS tissue was measured by neutron activation analysis in four ALS and three control cases. There was a significant difference between the average calcium content of ALS cases (4 19.108 ppm) and control cases (252f86 ppm). In ALS cases the significantly higher content of calcium was found in precentral, insula and hippocampal areas, also the thalamus, caudate nucleus, internal capsule, medulla and spinal cord. Mechanism of soft tissue calcification of CNS tissue in ALS cases and relationship of other divalent cations, especially manganese, to this process is discussed in regard to the etiopathogenesis of ALS.

Cross sections of negative-pion-induced reactions in 9Be, 12C and 19F nuclei between 0.4 and 1.9 GeV

Abstract Cross sections of negative-pion-induced reactions in 9Be, 12C and 19F have been measured at energies between 0.4 and 1.9 GeV by detecting the induced radioactivity. The excitation function of the 9Be(π−, πN)8Li reaction and those of the 12C(π−, π−n)11C and 19F(π−, π−n)18F reactions exhibit T = 1 2 resonances at Eπ = 0.6 and 0.9 GeV and a T = 3 2 resonance at 1.3 GeV. The resonance peaks are broadened apparently by the Fermi motion of the struck nucleon in the nucleus. The cross-section ratio σ( 9 Be (π − , π N ) 8 Li / σ π − p , where σπ−p is the free particle over the Fermi momentum, decreases rather monotonically like that for the (p, pn) reaction with increasing incident energy, while the ratios of σ(π − , π − n) σ π − n for the 12C(π−), π−n11C and 19F(π−, π−n)18F reactions are enhanced around Eπ = 0.6 GeV. This enhancement is explained partly by the charge exchange of the nucleon emitted from the Δ-particle formed through the decay of the T = 1 2 isobar. However, another mechanism should be needed to understand the enhancement of the (π−, π−n) reaction cross section around 0.6 GeV. The excitation functions for the 9 Be 6 He , 12 C ( 8 B , 8 Li ) and 12 C 6 He reactions indicate that the initial pion-nucleon.

Determination of aluminum in Pepperbush standard reference material by reactor neutron activation analysis.

リョウブ標準試料中のアルミニウム含有量を原子炉中性子放射化分析法により正確に定量した。Ge (Li) 検出器で測定されたγ線スペクトルの28Alのピーク面積は, 信号のパイルアップによる損失, 28Si (n, P) 28Alおよび31P (n, α) 28Al反応による28A1の生成率などに対して補正された。結果として, 600±40μg g-1のアルミニウム含有量が得られた。なお, これら補正係数の定量値に対する寄与は, 全体として4-10%であった。