I. Definition and identification of essential trace elements. The essential trace elements can be defined as the element essential in the diet of human beings less than 100 mg per day and their role are proved by following three kinds of methods. 1) Deficiency symptoms are detected in animals raised on diet which is deficient in specific element. 2) The element is a component of important substances, i.e. enzymes, vitamins or hormons. 3) Deficiency disease of the trace elements is observed in human being.

2. Deficiency disease in humans. Iron: sideropenic anemia, iodine: goiter, fluoride: dental caries, cobalt: pernicious anemia, zinc: acrodermatitis enteropathica, copper: Menke’s kinky hair syndrome.

3. Daily intake of trace elements for Japanese. Dietary survey was carried out on various groups of Japanese and daily intake of trace elements were calculated from the food tables presented in literatures.

4. Physiological and toxicological levels of essential trace elements. At a physiological level, trace element has biological action. With further increasing doses the element express its pharmacological action. At still higher dose this is followed by the appearance of toxicity. It is important to clarify the biological, pharmacological and toxicological levels of each trace element.

5. Current topics in essential trace elements. Trace elements in food is lost during food processing and refining practices. The modern day food tend to deficient in trace elements. New medical technics, e.g. artificial kidney, intravenous feeding etc., may induce deficiency or poisoning of trace element in patients if attention is not paied on the trace elements.

It has been reported that selenium (Se) had a preventive effect for Keshan and Kaschin-Beck’s Disease, and the erythrocytes of patients are low both in Se and in phospholipid (PL), particularly phosphatidyl-choline. On the basis of these facts we have determined the contents of Se and PLs in erythrocytes of Keshan and Kaschin-Beck diseased children and young dogs and guinea pigs fed with semipurified basal diet low in Se and PL, and the effect of Se and its mechanism of action was studied.

The blood Se and tissue glutathione peroxidase activity were lowered and the exhalent alkane and tissue chromolipid were elevated, and the Se diminished these changes.

Se maintained the normal level of total PL and the ratio between different composition of PL in cartilage, but in the heart the ratio of PL was improved only when adequate PL were given simultaneously. The membrane linking enzyme activity was slightly restored by Se supplement. Only when both PL and Se were given sufficiently the cytochrome oxidase activity in myocardium and cAMP level in plasma increased markedly and even more than that of the control group.

A systematic study of 44 elements in various Japanese seaweeds was carried out by chemical and neutron activation analyses. Marine phytoplankton, marine zooplankton and freshwater angiosperms were analyzed for comparative data. A method to compare multi-element data in many samples by the seawater concentration and ocean residence time of the element is proposed. Since the geochemical behavior of the elements is based on atomic properties, general similarity are observed among elemental compositions of many biogeochemical substances. The logarithmic correlation coefficients for several biological and geological materials with respect to element abundances were calculated. In this calcultion, if the elemental concentration .of the geochemical substances are normalized by those of seawater, the values of the correlation coefficients generally increase. The correlation seems to be due to the fact that the ocean has an important relationship with all organisms and their enviromental substances.

Selenium content of soybean protein was determined by a fluorometric method, and its nutritional efficiency was assayed by feeding weanling rats the diet containing either one of these materials at 15% protein level. Nutritional availability of selenium, as assessed by measuring the dietary intake and fecal output and by correcting for the metabolic obligatory fecal loss, ranged between 75 and 80%. The hepatic selenium level and glutathione peroxidase activity were found closely associated with the amount of nutritionally available selenium in the diet. Pepsin digestion of soybean protein isolate was accompanied by a concomitant liberation of dialyzable selenium. Pronase digestion of pepsin-and pancreatin digest soybean protein gave rise to selenium-containing substances which located on paper partition chromatography or thin-layer chromatography at the same positions where selenomethionine located. Analytical data obtained by GC“MS confirmed an existence of selenomethionine in the digest. These results indicate that selenium of soybean proteins occurs largely in the form of selenomethionine bound to proteins and its nurtitional efficiency is almost the same as selenite.

We have studied enzymologically the mammalian metabolism of selenocysteine, and shown that selenocysteine is synthesized by the coupled reaction of cystathionine β-synthase (EC 4.2.1.22) and cystathionine γ-lyase(EC 4.4.1.1) in rat liver. During the course of this study, we have found a novel pyridoxal enzyme, selenocysteine β-lyase, in a rat liver homogenate, which decomposes specifically L-selenocysteine into L-alanine and H₂Se. The enzyme occurs in various mammalian tissues such as livers, kidneys and hearts of rat, monkey and some others. We have purified the enzyme from pig liver to homogeneity and characterized it. The enzyme has a molecular weight of about 93,000 and consists of two identical subunits of molecular weight 49,000. The enzyme has an absorption maximum at 420 nm, and contains one mol of pyridoxal 5' -phosphate as a coenzyme per mol of enzyme. Its maximum reactivity is at about pH 9.0. The enzyme acts exclusively on L-selenocysteine. The following compounds are inert: DL-selenocystine; L-cystine, L-cysteine, L-serine, β-chloro-L-alanine, L-cysteinesulfinate, S-methyl-L-cysteine, Se-ethyl-DL-selenocysteine, L-homocysteine, selenocysteamine and selenocystamine. L-Cysteine (Ki=1.0 mM) inhibits the enzyme competitively with L-selenocysteine (Km= 0.83 mM).

Gerontological studies of blood and urinary selenium, hematological and physi- cal status of Japanese rural residents (273 male of 20-83 years and 430 female of 12-81 years) were carried out. The results obtained were as follows.

1. Mean blood Se concentration (mean±SD)were 132±29ng/ml for male and 122±24ng/ml for female.

2. Blood Se concentrations were decreased significantly with age both male and female.

3. Blood Se concentrations were most positively correlated with grasping power for male and hemoglobin concentrations for male.

4. Highest correlation between blood Se concentration and Se concentration in single-void urine corrected by density was observed.

To clarify the metabolism of macronutrients and trace elements in the process of pregnancy through delivery, specimens of the maternal and umbilical cord blood and placenta were provided from 21 healthy pregnant women at the time of delivery and various elements in the red blood cells (RBCs) and plasma of the above blood specimens and in the placenta were determined by ICP and AAS.

Principal findings are as follows:

(1)Elements, such as Ca, Mg and Sr, those are relevant to bone metabolism showed a statistically significant positive relationship in terms of their concentrations between the maternal plasma, the umbilical cord plasma and the placenta. Further, considerably high levels of Ca and Sr observed in some of the placental specimens, suggest the possibility of calcification in the tissue.

(2) Levels of Cu in the maternal plasma and of Zn in the umbilical cord plasma were higher than those in the umbilical cord plasma and in the maternal plasma, respectively. Levels of Cu in the umbilical cord RBCs and of Zn in the maternal RBCs were higher than those in the maternal RBCs and in the umbilical cord RBCs, respectively. These results suggest that the levels of Cu and Zn in the maternal and umbilical cord blood may reflect the concentrations of specific proteins that bind each of these metals.

(3) The levels of Mn, Cr and Pb showed statistically significant correlation with those of Zn, Sr, Ca, Mg and P in the placenta, suggesting the presence of the relationships in terms of the metabolism of the macronutrients and trace elements.

Since the enzyme, cysteamine oxygenase, has copper as essential metal for full enzyme activity, the effect of copper deficiency on the sulfur amino acid metabolism, especially taurine formation was examined. Animals were fed on the copper-depleted diet with different casein level (20% and 30%) for 6 weeks.

Serum and hepatic copper concentration were decreased in copper-deficient animals, but hepatic iron was increased. The hepatic cysteine dioxygenase activities of copper-deficient rats did not exhibited significant difference from that of control animals in either 20% or 30% casein level. Hepatic and urinary taurine concentrations of the deficient rats was not also altered compared to those of respective control animals. No significant change was observed in the hepatic cysteine and glutathione content in copper”deficient rats.

These results suggest that significant effect of copper deficiency on the taurine formation was not observed, further investigation of cysteamine oxygenase activity in copper-deficient status is necessary.

The effects of oral administration of molybdate+sulfate, molybdate+sulfide, tetrathiomolybdate (TM) and a high level of molybdate on the copper metabolism in rats are examined.

Either molybdate÷sulfide or TM but not molybdate+sulfate caused a decrease in systemic copper with a marked decline of caeruloplasmin (Cp) activity and the appearance of TCA insoluble copper fraction in plasma. On the contrary, a high level of molybdate produced a large increment in copper content of liver and plasma. Cp activity was kept at the level of control rats whereas more than half of plasma copper was in TCA insoluble form.

Gel chromatography of cytosol from liver and kidney cortex showed that any treatment of molybdate+sulfide,TM or a high level of molybdate was associated with the accumulation of copper and molybdenum in the fraction eluting with 1.2 of v/v₀ ratio.

The significance of these results in relation to the role of TM in copper-molybdenum-sulfur interaction in sheep is discussed.

The objective of this study was to clarify the effect of the administration of trace elements on those concentration in the body of Holstein cattle. Except for Se, feed intake and daily milk yields of treated cows were not affected by the administration of trace elements in the diet. There was a decrease in feed intake, rapid salivation, and swelling of the cervix and sore feet by the administration of 6.5 ppm Se. Most of trace elements administered was excreted in the feces and slightly secreted in the milk. Trace elements accumulation, distribution, and excretion of cows were different from the administration of each elements.

We usually use the word "normal" or "o;abnormal" about gustation. When we diagnose a patient who complains of hypogeusia as an abnormal one, a method of determination must be fixed and the normal range of taste acuity must be determined in the method. But nowadays, several normal range values are used, because determination methods are different.

In our study we wished to establish the median recognition threshols for four basic taste qualities in 72 healthy people. The median of recognition thresholds in the normal healthy subjects for sodium chloride was 30 m mols/1, for sucrose was 20mmol/l, for tartaric acid was 6mmols/l and quinine hydrochloride was 0.1mmols/l. We decided to cut down higher recognition thresholds in the frequency distribution of taste acuity as the standard range so仕ateach median comes to the place where recognition thresholds: have the largest frequency.

Male Wistar rats were separated into three groups (A, B and C). Group A was fed a calcium sufficient diet for 9 weeks, group B was fed a calcium deficient diet for 9 weeks and group C was fed a calcium deficient diet for 4 weeks and then calcium sufficient diet for 5 weeks. The significant changes in minerals were as follows: In blood, calcium and copper levels decreased, and magnesium and sodium levels increased in group B. Magnesium and iron levels increased in group C. In brain, calcium level decreased, and phosphorus and potassium levels increased in group B. Calcium level was decreased and pota_ssium and phosphorus levels increased in group C. In heart, calcium, phosphorus, copper, potassium and zinc levels decreased, and sodium level was increased in group B. Phosphorus level decreased in group C. In liver, magnesium, iron, zinc and sodium levels increased, and copper and potassium levels decreased in group B. Iron level was increased in group C. In spleen, sodium and magnesium levels increased, copper and potassium levels decreased in group B. Zinc level decreased in group C. In kidney, calcium, copper, potassium and zinc levels decreased and iron level increased in group B. Calcium and copper levels increased in group C. In bone, calcium, copper, potassium, magnesium, zinc and sodium levels decreased. In group C almost all elements recovered except calcium and copper. It is concluded that calcium deficiency causes various mineral changes and readministration of calcium do not recover these changes completely.

The study was carried out on 5 adult males (19-23 yr.) who were given 600 g of well-milled rice or 550 g of brown rice every day for 2 weeks. Those experimental diets contained 1.2 g per kg of protein and 46 kcal per kg per day of energy. The results obtained were as follows:

The wet and dry weight of feces was about 2 times in brown rice period compaired with in well-milled rice period.

The balances of nitrogen, Na, K, P, Ca and Mg showed almost similar values between both period of experimental diets.

As K, P, Ca and Mg which intake increased in order to take brown rice decreased their absorption rate, but on the volume of absorption, K, P, Ca and Mg were similar. Na, K, Cl, P, Ca and Mg concentrations in the plasma were normal in both experimental periods.

139 Samples of paddies were collected from 4 7 prefectural agricultural experiment stations and the elemental composition of their husks, brans and grains were determined.

The main purpose of the experiment was surveying mineral intake of Japanese from rice and also examining usefulness of husks as a biological indicator for environmental quality.

In this paper, contents of 20 elements - N, P, K, Ca, Mg, Fe, Mn, Cu, Zn, B, Si, Na, Sr, Ba, Al, Ti, Co, Ni, Cr, V - in husks were presented and briefly discussed about the meanings of their regional and varietal differences.

Dietary survey was carried out on male and female students of high school and university in Japan. Amounts of Ca, Fe, P, Na, K. Mg, Zn and Cu intakes from snack between meals were calculated by the food tables presented in various literatures using personal computer. The sufficient rate of Ca against its required allowance in these groups was 50-70 %. In the male students of high school and university, Fe intake was enough but shortage of Fe intake was remarkable in the female students. The contributive rate of snacks eating between meals in the daily mineral intake was highest in Ca, followed by P, K and Mg, and it was low in Fe, Na and Zn.

The effect of tryptophan metabolites, anthranilic acid (A. A.) and 5-hydroxyanthranilic acid ( 5-OH-A.A) on urinary bladder carcinogenesis in mice treated with N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) were studied.

ICR strain male mice were divided into 6 groups and given following additions in drinking water for 20 weeks. To group 1, no chemical, group 2, 0.025% BBN, group 3, 0.025% BBN and A.A. (0.5mg/mouse/day), group 4, 0.025% BBN and 5-OH-A.A. (same dose), group 5, A.A. only, and group 6, 5-OH-A.A. only were added.

Carcinoma of the urinary bladder developed in 11 of 30 mice (group 2), 5 of 30 mice (group 3) and 3 of 30 mice (group 4). Mice drinken tap water (group 1), only A.A. (group 5) and only 5-OH-A.A. (group 6) had no lesion of the urinary bladder except for occasional hyperplasia.

These result show that A.A. and 5-OH-A.A. inhibit the urinary bladder carcinogenesis in mice induced by BBN.

In the previous work, we reported the distribution of ³⁵S-taurine in rat neonates and adults using whole-body autoradiography. In the present work, the distribution of ³⁵S-cysteine,precursor of the taurine, in the mouse embryos (approximately 17 days of gestation), neonates ( 1-day-old) and dam was investigated by whole-body autoradiography and compared with that of ³⁵S-taurine, and [1-¹⁴C] cysteine (unpublished data). ³⁵S-cysteine was injected i.v. for the pregnant mice and i.p. for the neonates. Survival intervals were 30 min, 3 and 6 hours. In the dam, ³⁵S from ³⁵S-cysteine was highly incorporated into the pancreas, nasal and intestinal mucus membrane, Harder’s gland, bone marrow, hypophysis and mammary gland, while in the case of the embryo and neonate, it was highly accumulated in bone marrow, skin and hypophysis. When the data were compared with that of ³⁵S-taurine and [1-¹⁴C] cysteine, it was assumed that most of the ³⁵S in the pancreas, nasal and intestinal mucus membrane and Harder’s gland may present in the form of cysteine. On the other hand, in the maternal brain, ³⁵S from ³⁵S-cysteine was significantly incorporated into the pyramidal cell layer of the hippocampus and may present as taurine form. In the developing brain, radioactive sulfur from ³⁵S-cysteine was mainly found in the differentiating neurons of the cortical plate including primordial hippocampal cell layer and of the cerebellar cortical plate, and may be incorporated as cysteine form.

An experiment was performed using rats to examine the developmental mechanism of fatty liver from choline deficiency. As the result, it was found that the TG fraction in lipoproteins particularly LDL was markedly decreased. This finding is thought secondary to the hypofunction of liver microsomes from choline deficiency which results in decreased synthesis of serum lipoproteins especially LDL. Therefore, the liver’s movement of TG to other organs is decreased and leads to the pathological development of fatty liver from the resulting accumulation of liver TG.

The correlation between decreased LDL synthesis and LDL-Receptors in the fatty liver was studied, however, no conclusions could be made and further studies are required.

Feeding trial of Chlorella-extract was carried out on cultured ayu, Plecoglossus altivelis, in order to confirm the effect on improvement of physiological condition. The rearing with the extract supplemented diet during 50 days endowed some physiological effects as follows.

Despite no effect on weight gain, the supplement of the extract slightly reformed the fattened ayu to natural shape in addition to improvement of sensory evaluation in taste. In regard to body composition, the extract significantly depressed the body lipid level and changed the lipid class composition of the lipid reserve. Furthermore, in order to compare the mobilization pattern of body constituents to energy, the fish were kept during 21 days without feeding. The extract supplemented ayu was lower in loss of body weight under the starvation, because the reserved lipid was effectively mobilized to energy and protein was retained. Therefore it might be concluded that the Chlorella-extract activated lipid metabolism as lipid accumulation and lipid mobilization.

In 1984, it was observed that Li content in brain increased after administration of oyster to rats. And also tryptophan incorporation to brain was same between oyster administered group and Li₂CO₃ administered group.

Since Kimura reported that Zn content in the brain of Schizophrenic patients was decreased, we examined the effect of Zn ion on the Tryptophan Metabolism.

1) Some chelate agent especially EDTA inhibited the kynureninase activity and also higher concentrations of Zn ion inhibited the kynureninase activity in vitro.

2) In excess Zn ion administered group, kynureninase activity decreased and xanthurenic acid production increased. Therefore, optimum Zn was needed in physiological role of tryptophan metabolism.

(It is important that Oyster contains much amount of Zn)

For the purpose of elucidating the metabolic diturbances in schizophrenia, Kumura studied the content of zinc in the brain tissue by means of polarogramm.

The zinc content in frontal, occipital and hypocampal lobes of 10 cases of hebephrenic schizophrenia is significantly lower than other diseases.

Glycolysis in brain tissue is considered to follow the Emden-Meyerhof-Parnus process. Various enzymes controlling the reactions in the first half of glycolysis, are activated mainly by Mg⁺⁺ and Mn⁺⁺, while other enzymes, which catalyse the reactions in the latter half, are activated mostly by Zn⁺⁺.

The carbonic anhydrase (CA) is the most important zinc-containing metalloenzyme、andtake part in the elimination of CO₂. Hence zinc is pivotal from the viewpoint of respiratory gas exchange.

Hayashi confirmed the decrease of CO₂ in jugular blood of hebephrenic patients, especially in the period of their exacerbation.

Himwich and Altschule reported on the metabolic disturbances in hebephrenic patients as a delayed turnover of various glycolytic reactions and retardation of reaction against physical and mental stress.

In hope of correcting the metabolic disturbances of hebephrenic patients, we tried to give oyster’s extract, which contain large quantity of zinc, to several patients.

Fortunately every patient is getting better, namely affective flattening, poverty of speech and negativismus a. o. are gradually disappear.

The highly multi-branchedspherical structure of oyster glycogen (M. wt, 4x10⁵ ; CL, 12) was confirmed by repeated debranching actions with pullulanase. Comparison of molecular distributions of α-(1→4)-unitchains at each degradation step indicated that the outer-most unit chains (A-chain)have DP 6-9, and the middle layer consists of DP 6-12, while the inner-most region has DP 2 and 3 (molar ratio, 5 : 3). The core region, which corresponded 1% of the native glycogen, appeared to be a glycoprotein. The purified glycoprotein having M. wt., 1x10⁴, comprised 61.7% carbohydrate and 38.3% protein. The carbohydrate moiety contained glucose, mannose and galactose (6.1 : 1.5 : 1.0) together with N-acetylglucosamine. Amino acid analysis showed that the protein moiety consists of Gly., Lys., Glu., Asrt., Ser., and Tau (molar ratio, 1.06 : 1.52 : 0.76 : 0.69 : 0.56 : 0.39). This glycoprotein may play an important role in biosynthesis of glycogen.

The present paper deals with the inhibiting effect of oyster extract on the aggregation of human platelets, Oyster ( Crassostrea gigas) were extracted with hot water. Hot water extract of oyster inhibited the aggregation of human platelets induced by adenosine diphosphate (ADP), collagen, epinephrine and arachidonic acid. Gel filtration chromatography of the oyster extract on the column of Sephadex G-10 (NaBH₄ treated) demonstrated that the active substance existed in Fraction II and Fraction III. These fractions were consisted of nucleotidic compounds (5 '-AMP, cyclic-AMP, inosine etc.) and minerals.

Effects of an extract of oyster on serum lipids were evaluated in 22 subjects with a mean age 35.6 years who participated in the Kaike Triathlon (swimming of 3 km, cycling of 103.6 km and a marathon of 42.195 km) held in Tottori prefecture on July 25, 1984. Changes in serum lipids were studied before, during, and after the race.

The subjects ingested various doses of the oyster extract (12-20 tablets per day) from 3 weeks before the triathlon. On the day before the race, 12 tablets were administered after breakfast, lunch, and supper. In addition, on the day of the race, 12 tablets were given before starting as well as after swimming, cycling, and completing the race. Placebo was used in 11 subjects selected by a double-blind test. Blood was collected before breakfast (at rest) on the day before the race as well as after swimming, cycling and reqching the goal.

Measurements were made of blood glucose and serum lipids including free fatty acid, LDL, VLDL and chylomicron. Though no significant difference was observed between LDL receiving the extract of oyster and controls,, the former exhibited higher mobilization of free fatty acid and consumption of VLDL and chylomicron than the latter.