Shin-ichi Hareyama

Fractional catabolic rates of myosin and actin estimated by urinary excretion of N -methylhistidine: the effect of dietary protein level on catabolic rates under conditions of restricted food intake

1. Critical studies on the distribution of Ntau-methylhistidine (3-methylhistidine; Me-His) among organs and tissues in adult rats are reported. Adult rats contained 46-5+/-3-6 mg Me-His/kg body-weight. Almost 90% of the Me-His in the body was recovered from skeletal muscle. These results support the hypothesis that fractional catabolic rates of myosin and actin in skeletal muscle can be estimated by measuring urinary excretion of Me-His. 2. Dietary protein level did not affect the total amount of Me-His in the body. However, urinary excretion of Me-His increased as dietary protein intake was increased. 3. From these results it was concluded that fractional catabolic rates of myosin and actin increase as dietary protein intake increases.

Fractional flux rates of N-methylhistidine in skin and gastrointestine: the contribution of these tissues to urinary excretion of N-methylhistidine in the rat

1. Fractional flux rates of Ntau-methylhistidine (3-methylhistidine; Me-His) of skin and gastrointestine were measured by administering [methyl-3H]methionine to rats. 2. The results showed that the contribution of these tissues to urinary excretion of Me-His was at least 16-6%. This means that when fractional catabolic rates of myosin and actin were estimated from urinary excretion of Me-His, the part of Me-His derived from skin and gastrointestine should not be neglected.

Changes of the Rat Stomach Mucosa Induced by Calcium Deficiency

The present report describes an experiment to study the relationship between etiological factor (s) in allimentary tracts, especially stomach mucosa, and nutritional deficiency such as calcium deficiency.Basal diet resembled to a typical food ingredient in Japan was composed of mostly powdered polished rice, defatted soybean, soybean oil, salt mixture and vitamin mixture.Groups investigated were fed for 8 weeks with each test diet such as (I) low Ca, normal vitamin D, low vitamin A, (II) normal Ca, low vitamin D, low vitamin A, (III) low Ca, low vitamin D, low vitamin A, (IV) normal Ca, low vitamin D, normal vitamin A, (V) low Ca, low vitamin D, normal vitamin A, respectively.On the late period of the experiment, urine was collected to examine Ca and P excretion in such a condition.After animals were sacrificed, chemical analyses on serum, vitamins (liver vitamin A, renal thiamine and riboflavin) and skeltal matter were determined to judge the physiological condition of the animal, and stomach mucosa was histologically examined.Results indicated1) P excretion was greatly increased by Ca deficiency whereas Ca retention was rather even regerdless to Ca intake.2) Vitamin D considerably moderated mineral metabolism disorder induced by Ca deficiency, as judged from chemical analyses.3) Histological findings denoted Ca deficient diet might be a potential inducer of degenerative changes in rat stomach mucosa unless vitamin D was sufficiently administered.

Effect of Iodide on the Determination of Mercury in Biological Samples

It was well known that the presence of iodide had a negative effect on determination of mercury by the flameless atomic absorption photometry. In this case, however, a permissible amount of iodide differed from one another in workers. Then, the effect of iodide on the mercury determination was examined. As a result, up to about 1μg/ml iodide had no effect on the determination of up to about 0.01μg/ml mercury within the relative error ±4%.For the determination of mercury in tissues of rat the following method was applied.Tissues of rats were digested with perchloric acid-nitric acid mixture at 70-75°C overnight. The solution was diluted to 100ml with water, and then 5ml of sulfuric acid (1: 1) and 10ml of stannous chloride solution (10%) were added. 0.01-1μg of mercury was determined with 98-104% recovery in the presence of up to 100μg of iodide.

へき地学童の毛髪シスチン含量, 暗調応およびクレアチン排泄に及ぼす燐酸, ビタミン, メチオニンの服用あるいは牛乳飲用の影響

1) 貧しい食事をとっている学童にミネラル, 各種ビタミンあるいはこれとともにメチオニンを与えると, 毛髪シスチン含量が高まった。この投与物にさらに脱脂粉乳を加えると一層シスチン含量の増加がみられた。2) ミネラルとビタミンとだけの場合, あるいはこれとメチオニンを併用した場合に, 暗調応は改善されるがまだ正常でない。脱脂粉乳をこれとともに同時に与えるとはじめて正常になった。3) ミネラル, ビタミンとともにメチオニンを与えた群では尿中にクレアチンの濃度が増し, 体重増加も他のメチオニンを加えぬ群に比べて大であった。