The accumulation of the deposited soot is measured with63Ni 0.067 MeV β-rays using an end-window type G-M tube. The X-rays produced from breaking of β-rays and the radiations from active impure atoms in a source have influence upon the accuracy of measurement of thickness. Those impure atoms are mainly long lived60Co and59Ni. The63Ni is electroplated on copper plates in industrial plating solution containing63 NiCl2. The radiations emitted from these sources are counted through filters of 5.4 mg/cm22polyethylene or 540 mg/cm2 Al foil. Then counting rates of β-ray, X-ray and γ-ray components are obtained. The counting rates of β-rays and backgrounds fit respectively to the relation I∞ (1-e-μT) with differentt absorption coefficients, μ, as function of thickness of source, T (see Fig. 6) . The β-ray counting rate saturates at thinner thickness of the source layer because of higher self-absorption, At thicker thickness, the counting rates of background components are more dominant than that of β-rays. When thin source was prepared from the plating solution of low activity and the counting rate of β-rays is too low, the accuracy of the gauge is bad under the influence of natural background. From Eq. (17) and (18), the suitable thickness (at minimum Δx/x) of the source is obtained with the best accuracy. It is concluded that the method could be in the practical measurement of the concentration of soot-dust in a furnace.
32P-Diphosphoglyceric acid labeled at a single position was prepared, (1) Labeling at C-2. 3-Phosphoglyceric acid and32P-phosphoric acid were treated with dicyclohexylcarbodiimide in pyridine and the synthesized 32P-2, 3-diphosphoglyceric acid isolated by column chromatography. (2) Labeling at C-3, 32P-3-Phosphoglyceric acid labeled at C-3 was prepared by yeast fermentation and esterified with non-radioactive phosphoric acid by the same method as (1) . Two kinds of the labeled diphosphate were subjected to hydrolysis by dphosphoglycerate phosphatase prepared from rabbit muscle. The results revealed that the liberated phosphate comes almost exclusively from C-2 position but not from C-3 position. When hemolysate was incubated with added inosine and32P-phosphoric acid the radioactivity was incorporated into 2, 3-diphosphoglyceric acid, Diphosphoglycerate phosphatase was employed to determine the distribution of32 P. The isotope was shown to be evenly distributed between both of the phosphate groups. This can be explained by that both originate from a common inorganic phosphate pool.
Male rats of wistar strain, weighing about 100 g, were divided into the following 4 groups; 1) normal control rats, 2) blinded rats by removal of their both eye balls, 3) normal rats housed in complete darkness and 4) blinded rats housed in complete darkness. All of these animals were kept at a constant temperature of 20°C for 72 days. The cholesterol synthesis from acetate-14C by rat liver slice was found to be raised above the control level in blinded rats, normal rats housed in complete darkness and blinded rats housed in complete darkness. There was no difference in biosynthesis between normal rats housed in complete darkness and blinded rats housed in complete darkness. The cholesterol synthesis from mevalonic acid-14was slightly increased above the control level in normal rats housed in complete darkness. A rate controlling step in cholesterol biosynthesis appears to lie between acetate and mevalonic acid.
Cholesterol biosynthesis from acetate-1-14C and mevalonic acid-2-14C in normal or 48 hours fasted rat liver cell fractions was observed. 1. Biosynthesis in normal or 48 hours fasted microsome fractions was not changed. 2. Biosynthesis from acetate in fasted soluble fraction was inhibited, but biosynthesis from mevalonic acid was not changed. 3. Biosynthesis from acetate and mevalonic acid in fasted mitochondria fractions was depressed, and biosynthesis from acetate in normal mitochondria fraction was inhibited, but from mevalonic acid was not changed. 4. Biosynthesis from acetate and mevalonic acid in 48 hour fasted liver slice was inhibited, but from acetate in 24 hour fasted slice, was inhibited, but from mevalonic acid, was not inhibited. 5. These observations are suggested that the inhibitory substance resides in mitochondrial fraction and fasted soluble fraction.
A modified method for the determination of59Fe and55Fe. The59Fe activity is measured in a 2in×2 in NaI (T1) well crystal. This detector is not sensitive to the soft X rays of55Fe. The background is 100 cpm at efficiencies of 22% (liquid samples) and 6.5% (electroplated samples) for59Fe. The55Fe activity is measured from electroplated samples in a 3mm×1 3/4 in NaI (T1) crystal covered with 0.15 mm beryllium, which is preferentially sensitive to55Fe. In this condition the efficiency is 4.4% for55 Fe and 5.7% for59Fe, and the background is 150cpm. By means of a double radioisotope technique permitting determinations of the total amount of iron absorbed as well as the absorption rate, iron absorption was studied in a normal subject, in patients with iron deficiency, and in gastrectomized subjects with or without iron deficiency. When one mg radioiron as iron sulfate solution was administered orally, the shape of the plasma radioiron curve suggested that it might express the deference of two exponential functions. As a result, a new analytic method was devised to study kinetics of iron absorption. The iron absorption value calculated using this method was in good accord with that using the method of Hallberg and Sölvell. The initial absorption rate varied from 134 μg/hour to 3830 μg/hour in different subjects. Significant correlation was observed between the iron absorption value and the plasma iron disappearance half time, and between the rate constant from intestine to plasma and the serum iron level. In the patients with iron deficiency, the amount of iron absorbed into plasma during several hours was larger than in normal subjects, whereas the amount temporarily stored in the mucosa was not larger. In a gastrectomized anemic patient, when ferrous sulfate was given orally, the maximal absorption rate per 15 minutes was observed during the first 15 minutes following iron administration, and the absorption was not disturbed as compared to non-gastrectomized subjects, while the absorption of iron combined with egg protein was almost zero. These results may indicate that in some of gastrectomized subjects, although the ionization of iron from egg iron is disturbed, the absorption of iron salts in the intestine is not disturbed. Furthermore, the transportt of iron to the intestine is rapid.
The intestinal absorption of vitamin B12 was studied with the subjects hospitalized for the health examination in reference to the various gastric diseases, age and the presence of arteriosclerosis. All the cases, 62 subjects, from 29 to 70 years old, were preliminarily investigated with X-ray examination of stomach, lung and heart, gastrocamera, gastric juice, blood picture, serum iron, cholesterol-level, liver function tests, ECG, Ballistocardiogram, PSP, urine and stool analysis. The absorption tests of VB12was carried out by Schilling's method. One capsule of the radioactive57Co-VB12 (S.A. 1100 μc/mg, 0.48 g/capsule) was orally administered. In 14 cases of healthy subjects, the urinary excretion rate was 10.7-35.1% (mean 23.0±8.2%) . In 21 cases of atrophic gastritis, 10.7-42.8% (mean 22.3±7.1%), in 6 cases of gastric ulcer 18.5-24.8% (mean 23.0%), in 3 cases of gastric cancer 19.0-33.6% (mean 25.6%) . Thus, almost no differences in the urinary excretion rate between the healthy and gastric diseases were found. Furthermore, no relation to gastric acidity was found. The urinary excretion rate was further examined in reference to the age in all the subjects without gastric ulcer or cancer. Under the age of 39 years (11 cases) 18.8-35.1% (mean 26.0±6.0%) ; from 40 to 49 years old (12 cases) 13.5-42.8% (mean 24.5±8.3%) ; from 50 to 59 years old (17 cases) 10.7-46.3% (mean 23. 7±9.5%) ; above 60 years old (13 cases) 12.4-31.8% (mean 20.0±6.5%) . The urinary excretion rate gradually decreases with the ages, especially that of older than 60 years is significantly lower than that of younger than 39 years (p=0.1) . Our results suggest that the urinary excretion rate of the arteriosclerotic may be lower than that of the non-arteriosclerotic.