In an attempt to promote scientific argument and to attain a consensus on the dietary requirement (RDA) and oral reference doses (RfD) of trace elements, this lecture discusses both the present status of RDA and RfD in Japan and other countries and the background of the need to determine such values, including the methods of determination and their associated problems with an emphasis on how to overcome the confusion observed between essentiality and safety of these elements and other trace chemicals, including dioxins.

As a conclusion, the followings are recommended ; 1. The concept and determination of RDA and RID should be based on both updated scientific evidence and human hazard assessment rather than animal risk assessment. 2. The concept of chronic disease or ageing prevention should be included in the development of future RDA. 3. Greater coordination is need between policy makers in both nutrition and toxicology to avoid unnecessary confusion. 4. The process of translating scientific findings into public policy is urgently needed.

Zinc is concentrated in the limbic system, and sequestered in the presynaptic vesicles in a subclass of glutamatergic neurons. This metal may serve as an endogenous neuromodulator in synaptic neurotransmission, in addition to the function as zinc metalloproteins. In the present paper, zinc functions on epileptic seizures were studied using EI (epilepsy) mice and kinate (a seizure-inducing drug)-treated ddY mice. In EI mice and kinate-treated ddY mice, zinc concentration in the brain, especially in the hippocampus, a vesicular zinc-enriched region, was affected by seizures. Dietary zinc deprivation also significantly affected zinc concentration in the hippocampus. The susceptibility to epileptic seizures induced with kinate, which may decrease vesicular zinc, was enhanced by zinc deficiency. Therefore, zinc homeostasis in the brain, especially in the hippocampus, is closely related to epileptic seizures. The levels of GABA in the extracellular space in the hippocampus were remarkably increased during hippocampal perfusion with zinc. It is likely that vesicular zinc is involved in regulation of excitatory neurotransmission via glutamate.

Iron is an essential element and plays important roles in various biological systems, especially in the central nervous system. There is unincreasing number of epidemiological studies which indicate that children anemic in infancy continue to have poorer cognition, school achievement, and more behavior problems into middle childhood. Furthermore, the disorder of iron and iron-binding proteins in several neurodegenerative diseases such as Parkinson disease, Huntington disease, and Alzheimer’s disease have been reported. In particular, iron-responsive element is included in the mRNA of amyloid precursor protein, which is believed to be crucial in the pathogenesis of Alzheimer’s disease. Iron-supplementation therapy was reported to be effective in the cognitive disturbance of Alzheimer’s patients. Therefore, it is suggested that the abnormal iron metabolism may cause the disruption of iron-regulatory pathway and triggers various neurodegenerative processes.

Copper is an essential trace element which forms an integral component of copper-dependent enzymes, including cytochrome c oxidase, dopamine β hydroxylase, lysyl oxidase, Cu/Zn superoxide dismutase, tyrosinase and ceruloplasmin. Copper deficiency results in decrease of these enzyme activities. Menkes disease, a genetic disorder of a　copper-transporting ATPase deficiency, shows the typical manifestations of copper deficiency, including neurological disturbances, hypothermia, hair abnormalities and arterial abnormalities. These disorders are very severe and thus most patients die by the age of 3 years. In patients with mild type of Menkes disease, the characteristic neurological finding is ataxia, suggesting that mild copper deficiency causes ataxia.

Copper accumulation in the brain also damages the brain. In Wilson disease, another genetic disorder of copper metabolism, copper accumulates in the brain, resulting in neurological disturbances, including extrapyramidal symptoms and psycological disorders. In familial amyotrophic lateral sclerosis, a fatal progressive motor neuron disease, also, copper toxicity in motor neurons is suspected to contribute to the pathogenesis.

The high incidence of iron deficiency in developing countries is associated with their staple food composed largely of grains, vegetables and legumes. Food fortification is assumed to be an effective method for improving iron absorption. Sodium iron ethylenediaminetetraacetic acid (NaFeEDT A) is one of the food additives for iron fortification and it has been used for improvement of iron deficiency in the world. In this study, we determined the inhibition of tannic acid on iron intake of NaFeEDT A and ferrous sulfate (FeSO₄) in cannula preparation rats. The result demonstrates that tannic acid dose not inhibits for iron uptake of NaFeEDT A as fed with meals, indicating that NaFeEDTA is a suitable fortificant for iron fortification programs in developing countries.

To investigate the distribution of the arsenic accumulated by Hijiki plants, we collected Hijiki plants along the seashores of Tushima Archipelago, Japan in May. Hijiki plants were separated into several parts such as leaves, stems and roots. After washing them with distilled water, the samples were lyophilized. Arsenic was determined by neutron activation analysis in the nuclear reactor of Research Reactor Institute, Kyoto University. The arsenic localization in individual plants along their stems was not uniform, when expressed in μg arsenic per g of wet or dry weight (ppm) as well as μg arsenic per unit length of the stem. This may suggest that the accumulating process of arsenic changes during their growth, reflecting at least partially the variable environmental conditions of the ocean.

Much interest has been focused on the potency of vanadyl (VO) complexes as an orally active antidiabetic agent. Because the numbers of insulinomimetic VO complexes reported to date are still limited, we prepared a new series of VO complexes with ligands containing phosphonate group.

In vitro insulinomimetic activities of the complexes were higher than that of VOSO₄ (VS) in terms of IC₅₀ value, 50% inhibition concentration of VO complex on epinephrine-stimulated free fatty acids (FFA) release from isolated rat adipocytes. Among them, a vanadyl-N-(phosphonomethyl) iminodiacetate (VO (pida)) complex exhibited the highest activity. In in vivo trial, high blood glucose levels of streptozotocin-induced diabetic rats (STZ-rats) were normalized within 7 days after daily oral administrations of the complex, and glucose tolerance of rats was improved. From the results, it was concluded that vanadyl-phosphonate complexes are proposed to be a new candidate for orally active therapeutic of type 1 diabetes mellitus.

Leptin is a peptide hormone that is secreted primarily from adipocytes, and acts as a key signaling factor for regulating appetite and energy balance. Several studies have demonstrated that insulin increases leptin protein secretion probably through the change of glucose metabolism. Vanadium has been reported to possess insulin-mimetic activity and stimulate glucose uptake on various types of cells. The purpose of this study was to examine the effect of vanadium on leptin secretion from rat adipocytes. Insulin and vanadyl sulfate stimulated in leptin secretion from rat adipocytes after 2h of treatment. Phosphatidylinositol 3-kinase inhibitor, LY294002 decreased both insulin- and vanadyl sulfate-stimulated leptin secretion. On the other hands. mRNA levels for leptin were decreased by vanadyl sulfate. though insulin treatment did not significantly affect leptin mRNA synthesis. These findings suggest that vanadium decreases leptin gene synthesis, but stimulates leptin protein secretion through the phosphatidylinositol 3-kinase pathway.

To clarify effects of over dose or under dose of calcium intake in mature female rats were studied. Wistar mature female rats, over 25-wk-old, multipara (over 4 paras), were divided into five groups and diets of different amount of calcium ; (1) Ca 1/10 times, (2) Ca 1 times (control), (3) Ca 2 times, (4) Ca 5 times, (5) Ca 10, times were given for 4 weeks. Hematological parameters and biochemical parameters in plasma were monitored. ALP levels significantly decreased in the rats fed with low Ca diet (Ca 1/10) compared to in control rats. GOT, GPT and UN levels significantly increased in the rats fed with high Ca diet (Ca 10) compared to in control rats. TIBC levels significantly decreased in the rats fed with high Ca diet (Ca 5, Ca 10) compared to in control rats. These results suggest that not only low intake of Ca but over intake of Ca is fallen into ill health.

Oral administration of tributyltin chloride (TBTC) is known to cause thymus atrophy and suppression of the T-cell dependent immune responses. To study the mechanism underlying the thymus atrophy, induction of apoptosis was investigated. Oral administration of TBTC (100 mg /kg in NMF diet) enhanced the fragmentation of DNA in the thymus. Activation of DNase was observed along with the fragmentation of DNA. The apparent molecular mass of the DNase was 18 kDa, suggesting the activated DNase was NUC18. Activation of Caspase-3 was observed, indicating the activation of caspase cascade. In addition, FasL levels were increased in response to the administration of TBTC. Taken together, these data show that the induction of apoptosis in the thymus by the administration of TBTC is mediated by the FasL/Fas dependent pathway, which results in the activation of both Caspase cascade and DNase (NUC18).

In this study, we observed the effects of both inorganic and organic arsenic compounds on immune functions of murine peritoneal macrophages (PMs) in vitro. An inorganic arsenic compound, arsenite, was strongly toxic to PMs, and the concentration of it that decreased in the number of surviving cells to 50% of that in untreated controls (IC₅₀) was 8.5 μM when the cells were incubated with arsenite in the presence of recombinant murine interferon γ (IFN γ; 10 U/ml) and lipopolysaccharide (LPS ; 100 ng/ml) for 48 h. Also, arsenite induced necrosis in PMs, inhibited strongly the nitric oxide secretion from PMs, and markedly enhanced the secretion of an inflammatory cytokine, interleukin 1α (IL-1α ) , from these cells during the induction of cell death. In contrast, the cytotoxicity of an organic arsenic compound, dimethylarsinic acid (DMA), which is the final methylated metabolite of inorganic arsenic compounds in humans, is very weak ; IC₅₀ value of DMA was 3 mM. Interestingly, DMA selectively induced apoptosis in PMs and decreased in the secretion of IL-1α from these cells, although it inhibited NO secretion. Taken together, the methylation of inorganic arsenic compounds in humans plays an important role in suppression of severe immunosuppression and inflammatory responses caused by inorganic arsenic compounds.

Zinc (Zn) in Japanese oyster (Crassostrea gigas) was extracted and its bioavailability was evaluated. Extraction with 0.1N HCl was performed on a boiled Japanese oyster. After neutralization of the acid extract, precipitation formed was collected and used as the acid soluble fraction of boiled oyster (ASFO). Zn content of the ASFO was 3 to 10% in the dry basis. More than 70% of total Zn of raw Japanese oyster was recovered in the ASFO. In the fractionation by HPLC using TSK-GEL G2000SWXL, Zn in the ASFO was recovered in a single peak fraction with a molecular weight of about 6800. Zn level in this peak was increased by an exogenous addition of zinc chloride to the ASFO. Male weanling Wistar rats were pair-fed a low-Zn basal diet (Zn content, 1.4 ppm) or the basal diets supplemented with 5 ppm of Zn as zinc carbonate or the dry powder of the ASFO for 4 weeks. Zn contents of liver and tibia of the rats fed the diet supplemented with the ASFO were significantly higher than those of the rats fed the diet supplemented with zinc carbonate. These results indicate that Zn contained in the ASFO is more available than Zn in the form of zinc carbonate.

Levels of systolic blood pressure (BP) observed immediately before the start of dietary conditioning were significantly higher in spontaneously hypertensive rats (SHR) than in Wistar Kyoto rats (WKY). However, levels of systolic BP and basal mean arterial pressure (MAP) observed at the end of dietary treatment for 4 weeks were SHR fed a Zn-deficient diet > SHR fed a standard diet > WKY fed a standard diet ≒ WKY fed a Zn-deficient diet. Administration of the nitric oxide synthase (NOS) inhibitor, L-NAME caused an increase in MAP levels in SHR fed a standard or a Zn-deficient diet, demonstrating the involvement of the vasodilator, nitric oxide (NO), in the regulation of systemic BP in a genetically hypertensive state. On the other hand, administration of the superoxide scavenger, tempol, led to a decrease in MAP levels in SHR fed a standard or a Zn-deficient diet, indicating the participation of the oxygen free radical, superoxide, in an increase in systemic BP in a genetically hypertensive state. As reported recently, the mechanism involved may be due to a decrease in the action of the vasodilator, NO, based on the formation of peroxynitrite coming from the non-enzymatic reaction of superoxide and NO. In addition, tempol treatment completely restored MAP levels in SHR fed a Zn-deficient diet to levels comparable to those observed in SHR fed a standard diet, indicating that a further increase in systemic BP levels seen in SHR fed a Zn-deficient v.s. a standard diet may be brought by a reduction in the action of the vasodilator, NO, resulting from an increase in superoxide. The activity of the superoxide scavenger, Cu/Zn-superoxide dismutase (SOD), in the thoracic aorta was significantly decreased in SHR fed a Zn-deficient diet relative to SHR fed a standard diet. It appears that a decrease in the activity of Cu/Zn-SOD observed in the thoracic aorta of SHR fed a Zn-deficient diet at least in part plays a role in an increase in superoxide in this model. Thus, Zn deficiency may be a crucial factor to develop genetic hypertension presumably through the oxidative stress caused by superoxide.

We synthesized new insulinomimetic zinc(II) complexes of amine derivatives with Zn(Nn) coordination mode. The insulinomimetic activity was estimated by the inhibitory effect on free fatty acid release from the isolated rat adipocytes treated with epinephrine. Zn (2-ampy)₂, Zn(1,5,9-TN) etc. with the stability constants (log β) lower than 11 have been found to have higher insulinomimetic activities than that of ZnSO₄. In in vivo studies, the high blood glucose level of KK-A^y mice with hereditary type 2 diabetes mellitus was lowered by daily intraperitoneal injections of Zn(2-ampy)₂ for 14 days. We proposed here that new zinc(II) complexes with Zn(N₄) coordination mode have high insulinomimetic activities and blood glucose normalizing effects.

Guanidinobutyrase purified from Arthrobacter sp. does not contain Mn²⁺. but about 1.0 mol of Zn²⁺ per mol of subunit. The enzyme was completely inactivated by 1,10-phenanthroline. The inactivated enzyme was markedly reactivated by incubation with Zn²⁺ or Co²⁺. The replacement of Zn²⁺ by Co²⁺ resulted in significant changes in Vmax values without any change in the Km values for substrates, 4-guanidinobutyrate and D-arginine. The results suggest that the main function of the metal ion is not in binding of substrate to the enzyme, but is in the hydrolysis of the substrate. The reconstituted enzymes with Co²⁺ (Co²⁺-enzyme) showed a different substrate specificity from that of Zn²⁺-enzyme. The predicted amino acid sequence of the enzyme consists of three regions of high homology to Mn²⁺-dependent amidinohydrolases as agmatinase of Escherichia coli, and arginases of Bacillus subtilis and rat liver.

Euglena gracilis, a single cell organism with plant and animal characteristics is useful tool in studying cellular response to various chemical stresses. E. gracilis strains Z and achlorophyllous mutant SMZ were used in this study. In elucidation of the mechanism of the cellular response to the chemical loading in E. gracilis, we hypothesized that G-protein and phosphatidylinositol biphosphate mediated signal transduction pathway participates in the cellular response of E. gracilis. Then, changes of their morphology, deflagellation and the intracellular calcium level by tributyltin chloride (TBTCl) were compared concerning several calcium agonists and antagonists. By 50μM of TBTCl loading on Z strain, a lost of cell motility, morphological change, deflagellation and increase of intracellular calcium level were observed, however, halt of cell motility without distinctive morphological change and a behavior of intracellular calcium level were observed in SMZ strain. Interestingly, the response to a concentration jump of inositol 1, 4, 5-trisphosphate (10 nM) loading in Z and SMZ strain was not the same, suggesting some difference in inositol 1, 4, 5-trisphosphate mediated signal transduction system.

The gene encoding an L-glutamate oxidase from Streptomyces sp. X -119 -6 was cloned in Escherichia coli. The nucleotide sequence of the L-glutamate oxidase gene revealed an open reading frame of 2, 103 bp. encoding a 701-amino acid protein. The deduced primary structure shares 15.8% sequence identity with the L-amino acid oxidase, including the consensus amino acid sequence, -GXGXXG-. which is contained in β α β-fold binding the ADP at N-terminal region.

We constructed an expression plasmid (pKK-LGOX) and E. coli harboring pKK-LGOX was expressed the L-glutamate oxidase precursor. The molecular mass of precursor was 76 kDa and it has homodimer structure, but an enzyme from Str. sp. X-119 -6 has α2β2γ2 subunit structure, and it has the different enzymological character with an L-glutamate oxidase from Str. sp. X-119-6. To improve of affinity to substrate of an L-glutamate oxidase precursor, enzyme was digested with trypsin and isolated by gel-filtration. Two fragment (58 kDa and 18 kDa) was detected by SDS-PAGE, and its Km value is 0.2 mM, but precursor’s Km is 5 mM. It is suggested that digesting the enzyme by trypsin is separated the β subunit from precursor, and originated affinity to substrate.

Content of several minerals (sodium (Na), magnesium (Mg), aluminum (Al), calcium (Ca), manganese (Mn), iron (Fe), nickel (Ni) and zinc (Zn)) in 27 samples of Japanese green tea leaves were determined by inductively coupled plasma spectrometry. The 27 samples were consisted of ones cultivated at Nan-sei islands (n = 3), Kyushu island (n = 8) , Shizuoka Prefecture (n = 10) and other places (n = 6) in Japan. Median value of the content of each mineral was as follows (mg/ 100 g dry leaf) : Na, 1.7; Mg, 141.6; Al, 33.9; Ca, 228.3; Mn, 50.2: Fe, 7.0; Ni, 0.4; Zn, 2.1. A regional variation was observed in Na, Mg, Ca and Zn contents. Infusion rates of Ca, Fe, Mn and Mg were 6.9, 10.9, 16.5, 23.9 and 33.4% respectively. These results indicate that an intake of green tea drink highly contributes the daily intakes of Mn and Al in Japanese population.

Effect of inorganic ions on texture of cooked rice was investigated. Rice was cooked in 100 ml beaker and its hardness and stickiness were directly measured with a rheometer. When rice was cooked in 0.5 M NaCl or KCl, the hardness and stickiness were significantly increased compared to that cooked in a deionized water. The weights of rice gruel with inorganic ions were lower than that prepared in the deionized water. However, a difference in the water content was not observed between the cooked rice with and without 0.5M NaCl. When rice was cooked with several kinds of commercial mineral water, its hardness and stickiness were decreased. These results indicate that inorganic ions contained in cooking water appear to alter the texture of cooked rice.

The mechanisms of biosynthesis and repair of iron-sulfur clusters are still unclear. In E. coli, the iscU gene is proposed to be involved in the formation of iron-sulfur cluster. We cloned iscU gene from E. coli and expressed IscU tagged with six histidines at its C-terminus. Proteins which specifically interact with IscU were screened by "pull-down" assay by using a nickel-chelating column, resulting in finding that IscS interacts with IscU. A disulfide bond was formed between IscS and IscU, which was induced in the presence of 0.1 mM hydrogen peroxide in a cultivation medium. The disulfide bond was formed specifically between Cys63 of IscU and Cys328 of IscS. Cys63 of IscU is thought to play an important role as a ligand for iron-sulfur cluster. Cys328 of IscS is essential for its enzymatic activity. Cys63 of IscU and Cys328 of IscS probably exist in a short distance in the IscU-IscS complex, and they may form a covalent complex under oxidative condition.

Hepatocellular carcinoma is one of the most frequent human tumors worldwide, and commonly evolved from chronic hepatitis and liver cirrhosis. It is therefore very important to detect and evaluate the progressing state of chronic hepatic disorders. Serum Cu and Zn levels and particularly their ratios are frequently reported to be good signals for diagnosing various diseases, including hepatic disorders. In the present study, the serum Cu/Zn ratio of patients with different hepatic diseases was confirmed to be significantly higher than those of the control. However, high diagnostic accuracy was not obtained by using the Cu/Zn ratio. On the other hand, serum MT levels of patients with liver cirrhosis and hepatocellular carcinoma were significantly lower than those of the control and chronic hepatitis. Thus, we introduced a new parameter, the (Cu/Zn) /MT ratio, to examine a possibility for diagnosing hepatic disorders. The calculated ratio distinguished the two groups, namely, the [control+ chronic hepatitis] and [Liver cirrhosis + hepatocellular carcinoma] groups ; 88.6% of the patients with liver cirrhosis and hepatocellular carcinoma were classified by this ratio as members of the [liver cirrhosis and hepatocellular carcinoma] group. On the basis of these results, we propose a new method to diagnose the pathophysiological changes of patients from chronic hepatitis to liver cirrhosis by using (Cu/Zn) /MT ratio.

Induction of apoptosis of HL60 cells by gallic acid derivatives was analyzed in relation to its prooxidant action. Gallic acid esters with long hydrophobic alcoholic chain showed potent apoptotic activity. Octyl-and laurylgallates induced apoptotic cell death of HL60, whereas gallic acid, ethyl-, propyl-and butylgallates caused only a little apoptosis. Octylgallate inactivated aconitase prior to the induction of apoptosis of the cells. Treatment of cells with antibodies to Fas and TNF did not affect the octylgallate-mediated apoptosis, suggesting that Fas or TNF signaling pathway is not responsible for the apoptosis by gallate derivatives. Gallic acid esters with hydrophobic chains can generate superoxide radical and then hydroxyl radical through the inactivation of aconitase in cells. Gallate esters-dependent formation of reactive oxygen species may participate in the apoptosis of HL60 cells.

Protective effects of dipicolinic acid (pyridine 2,6-dicarboxylic acid) on copper-dependent LDL oxidation and DNA strand breaks were analyzed in relation to the inhibition of the copper reduction. Dipicolinic acid inhibited the copper-mediated oxidation of low density lipoprotein, whereas other pyridine carboxylates showed only a little protective action. Dipicolinic acid further exhibited the copper-dependent DNA strand breaks. Dipicolinic acid showed a potent inhibitory activity against copper reduction by LDL itself and gallic acid. Protection by dipicolinic acid against copper-dependent injuries of LDL and DNA can be explained by the inhibition of copper reduction, that is the formation of cuprous ion the prooxidant.

Tanbaguro (Glycine Max Merrill Forma Kuromame Makino), one variety of black soybeans harvested in Tanba district in Kyoto, was examined from the view point of carbohydrate composition of cell wall polysaccharides and water-soluble oligosaccharides.

This report indicated the possibility of Tanbaguro as a functional food, compared with other kind of black soybeans, Banseihikariguro, harvested in Hokkaido.

Raw Tanbaguro containes stachyose, that is known as one of soybean oligosaccharides, as much as raw Banseihikariguro. However Tanbaguro containes more oligosaccharides than that of Banseihikariguro when there are boiled. This might be concerned the rheological proparties of cellwall polysaccharides, especially water-soluble and hot water-soluble polysaccharides. Tanbaguro was higher in the esterification % of water-soluble and hot water-soluble polysaccharides than those of Banseihikariguro.

Since the role of nutrition and meals has been thought to vary with sport athletics, nutritional intake appropriate for the individuals' characteristics has been reported to be important in the recent years. We assessed diets to improve iron deficiency in university middle- and long-distance female runners by conducting one-year follow-up of those runners and ordinary female students with regard to the nutritional intake, physique and hematological profile. No difference was observed in the BMI between the two groups, whereas the runner group had the significantly lower % of body fat. The energy, iron, vitamins B₂ and C intake was significantly higher in the runner group than in the student group, but the energy and iron intake did not meet the allowances. Neither group showed any significant change in the physique or physical composition after one year. No one exhibited manifestations of malnutrition or anemia. However, the runners who were suspected of having iron deficiency failed to achieve any improvement. The serum iron levels correlated to the amounts of iron, beans and fruits ingested, and the serum ferritin levels correlated to the amounts of greenish yellow vegetables and other vegetables ingested. In addition, a correlation between the amount of iron intake and the amounts of beans, vegetables and fishery products was observed. The above-mentioned findings indicated that it is important for the middle- and long-distance runners to have a diet providing an iron intake of over 12mg to improve iron deficiency by trying to include beans, seafood and vegetables in particular.

Affinity columns of two unique α-mannose-binding lectins, isolated from bulbs of Zephyranthes carinata (ZCA) and Crocus vernus (CVA), the latter highly specific to Man (α-1,3) Man, were used as probes of biochemical fractionation of glycans and glycoproteins. Thus, the α-mannan of yeast cell-wall was selectively separated from glycogen, either by CVA or ZCA column. The horse radish peroxidase glycoprotein (PDG), which contains biantennary mannose-terminated carbohydrate moiety, was purified by ZCA-column. When the purified PDG was further applied onto CVA column, two fractions were separated, one (65 %) not retained on the column, and the other (35 %) retained was eluted with 20mM diaminopropane (DAP), suggesting structural heterogeneity of PDG, with regard to the carbohydrate sequence.

The ZCA-column, strongly binds to terminal a-mannose residues (Man), was used for fractionation of brewing liquor products, including several kinds of commercial beer and "happou-shu", wine and also sake, and to provide a one-step microanalysis of content of yeast mannan. A small aliquot of each sample was dialyzed, and the non-dialyzable fraction (Mw. > 6,000) was applied onto the affinity column, from which starch and other non-retaining polymers were removed. The column retained α-mannan, which should be liberated from yeast during fermentation process was eluted with 20-40mM DAP. Thus, most of commercial beer (either domestic or imported) showed similar elution profiles and mannan contents, 20-25mg / 100ml of beer, whereas all "happou-shu" samples showed lower mannan contents, approximately 10mg/100ml, suggesting different brewing process. On the other hand, the sake samples were shown to contain 60mg/100ml of mannan, their elution profiles were not same from each other, probably due to a variety of fermentation process.

Cadmium ( Cd) is an environmental pollutant that causes adverse effects in organisms, however, it remains unclear how Cd enters cells. Metallothionein (MT) plays an important role in Cd detoxification. In a previous study, we demonstrated that Cd traverses cells partly via a high-affinity transport system for manganese (Mn) using a Cd-resistant cell line (Cd-rB5) from immortalized MT-null mouse fibroblasts and that the suppression of this pathway is one of the determinants of the reduced susceptibility to Cd in Cd-rB5 cells. To clarify the role of the transport system for Mn in the cytotoxicity of Cd. we investigated the modulation of cytotoxicity and accumulation of Cd by Mn. using Cd-rB5 and their parental cells. Simultaneous addition of MnCl₂ to a medium alleviated the cytotoxicity of Cd in parental cells dose-dependently. In parallel. the accumulation of Cd in parental cells was reduced by the addition of MnCl₂ in a dose dependent manner. However, simultaneous exposure of Cd-rB5 cells to Mn did not modulate the cytotoxicity and accumulation of Cd. These results suggest that Mn may act as a competitor for Cd in entering cells, leading to the reduction of cytotoxicity of Cd. The cytotoxicity and accumulation of Cd in MT-null parental cells was attenuated also by ZnCl₂. but not by CoCl₂. NiCl₂. FeSO₄ or CuCl₂. suggesting that Zn may also have an affinity to the transport system for Mn and Cd. Thus, in addition to MT. the inhibition of cellular Cd uptake by Mn may be an important factor for detoxification for Cd.

A number of studies on the role of Se in biochemistry are found in literature. Selenium is one of the essential trace elements. Thirteen Se-containing proteins have been found in organs of rat. It is also reported that Se is in a competitive or synergetic relationship with many metals such as Ag, Pd, Zn, Co, Cd, Bi, Sn, Mn, Te, Pd, W, Mo, Tl, Cr, Ni, Fe, Au, As, Pt and Cu. In the present study, the uptake and the distribution of trace elements in Se-excessive, Se+As-excessive,and As-excessive rats examined by the multitracer technique, which can be used to evaluate the behavior of many elements under the same experimental condition. We describes the interaction between Se and some elements containing multitracer.

The genes encoding mammalian thioredoxin reductase (TrxR) isozymes, TrxR1 and TrxR2, were cloned from a human lung adenocarcinoma cell line, NCI-H441. TrxR1 gene was amplified by conventional thermal cycle program to give an intensive signal on agarose gel electrophoresis. mRNA from normal lung cells also produced the amplified TrxR1 gene by the same RT-PCR procedure. In contrast, the amplification of TrxR2 gene from the NCI-H441 cells required the touch-down PCR program in which the annealing temperature was decreased from 75 to 65 degree by 0.4 degree in every cycle. The normal lung mRNA sample failed to yield the TrxR2 gene, suggesting even smaller expression in the normal cells. The amplified genes were cloned on TOPO TA vector and sequenced to identify the sequences.

We synthesized L-homocysteinesufinic acid and L-homocysteinesulfonic acid, analogs of L-glutamic acid from L-methionine with overall yield of 18 and 30%, respectively. L-Homocysteinesulfonamide was synthesized as an analog of glutamine with an overall yield of 3%. Their reactivities with various enzymes acting on glutamic acid and glutamine were examined. L-Homocysteinesulfinic acid reacted with glutamate dehydrogenase (K_m=13.3 mM, V_max=2.46 U/mg), glutamate decarboxylase (K_m=38.4 mM, V_max=2.39 U/mg) and glutamate oxidase (K_m=2.42 mM, V_max=22.8 U/mg). It competitively inhibited glutamate decarboxylase (K_i=6.23 mM). L-Homocysteinesulfonic acid did not react with all the enzymes tested, but searved as a competitive inhibitor of glutamate decarboxylase (K_i=1.24 mM). L-Homocysteinesulfonamide competitively inhibited glutaminase (K_i=4.27 mM) and asparginase (K_i=27.2 mM).

ヒ素は生態系を含む自然環境中において普遍的に分布しており,水圏生態系においてもさまざまな化学形態を取りながら存在している。しかしヒ素は生物に対して毒性が高いため,環境影響評価の観点からヒ素の生体影響について明らかにされねばならない。一般的にヒ素は主に飲料水や食品を介してヒトに侵入するが,特に海産生物に多量に含まれているため,多量のヒ素が海産食品を介してヒト体内に侵入することが考えられる。これまで海産物摂取によるヒ素中毒は報告されていないが,ヒ素による健康影響への懸念は残る。ヒ素のヒトに対する影響や生体内挙動は,ヒ素の化学形態に大きく依存することが考えられるため,ヒ素の化学形態別分析が必要であり,得られた結果について総合的に評価することが重要である。ヒ素の化学形態別分析法として,最近では HPLCあるいは ICによりヒ素化合物を分離した後, ICP-MSで検出する方法が多く用いられるようになってきた。しかし,これまで報告されている分析方法では分離に多くの時間を要し,アルゴンの消費量も多いため,ランニングコストが問題点となっていた。本研究では HPLC/ICP-MS分析を行う際の省資源化を実現するために,逆相担体を充填したセミミクロカラムを用いてヒ素化合物を分離し, ICP-MSで測定する高感度でかつ迅速な一斉分析法について検討し,淡水生物,海産生物ならびに海産物摂取後の尿中ヒ素の形態別定量を行ったので報告する。

Patients with diabetes mellitus are increasing in the world. Recently, we have reported that vanadyl ion and its complexes normalize the blood glucose levels of streptozotocin-induced type 1 diabetic rats. When they will be used clinically in the future, it is indispensable to understand the pharmacokinetic behavior of vanadyl compounds. Therefore, we examined the features of vanadyl states in the blood of healthy rats after oral or intraileal administration of three vanadyl compounds (VS, VO (pic)₂ and VO (6mpa)₂) by using electron spin resonance, and found that vanadyl compounds are mainly absorbed from the ileum. On the basis of the results, we attempted to use the enteric coated capsule containing VO (6mpa)₂. Bioavailability of VO (6mpa)₂ was improved by the capsulation, and high vanadyl concentrations in the blood were kept continuously. In conclusion, enteric coated capsulation of vanadyl complexes is a useful method to treat diabetes mellitus.

Zn(II) complexes with amide derivative ligands exhibited the in vitro insulinominetic activities in isolated rat adipocytes treated with epinephrine in terms of inhibition of free fatty acid release. It was found that the blood glucose levels are normalized by daily intraperitoneal injection of Zn(II) complexes with 2-picolinamide(pa-a) and 6-methyl-2-picolinemethylamide(6mpa-ma) for 14 days in KK-A^y mice who are a model animal with hereditary type 2 diabetes mellitus (DM). After the administrations of the complexes for 14 days, improvement of the glucose metabolisms was confirmed by an oral glucose tolerance test. In addition, the hemoglobin A_1c, which shows the average blood glucose levels over a long period, was improved. Based on the results, Zn(II)-picolinamide derivative complexes are proposed to be a possible therapeutic agent to treat type 2 DM.

To examine the effect of hyperbaric oxygen on Zinc (Zn) deficient rats, we investigate the morphological changes and expression of inducible nitric oxide synthese (iNOS) and ED1 in lung of rats after hyperbaric oxygen exposure. Seven-weeks-old male Spreague-Dawley (SD) rats were fed on diets supplemented 0 or 0.02% Zn for 60 days. They were exposed to 2.8 ata for 60 minutes by 100% oxygen and examined pathohistological changes and expression of iNOS and EDI in lung. In 0% Zn diet, sever morphological changes and strong expression of iNOS and EDI were found. However, number of (WBC) did not increase in 0% Zn diet. These results suggest that the hyperbaric oxygen stress causes sever lung injury in Zn deficiency compared to normal condition.