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Author

Tetsuro Hongo

Other affiliations: University of Tokyo
Bio: Tetsuro Hongo is an academic researcher from RMIT University. The author has contributed to research in topics: Mercury (element) & Population. The author has an hindex of 15, co-authored 45 publications receiving 645 citations. Previous affiliations of Tetsuro Hongo include University of Tokyo.

Papers
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Journal ArticleDOI
TL;DR: The relationships among element concentrations and stable carbon and nitrogen isotope ratios in animals consumed by the people called Gidra, who inhabit the lowland of Papua New Guinea, were examined to indicate that Hg was an element which accumulates in animals along the food chain.

57 citations

Journal ArticleDOI
TL;DR: Hair and urinary mercury concentrations were correlated significantly (r = .59), indicating that urinary mercury excretion was elevated because fish consumption was very high.
Abstract: Hair and mercury concentrations of 134 fish-eating subjects in the Lake Murray area and 13 non-fish-eating subjects in the upper-Strickland area, Papua New Guinea, were studied. Hair mercury levels among the subjects in the Lake Murray area (mean = 21.9 μg/g, range = 3.7–71.9 μg/g) and urinary mercury levels (mean = 7.6 μg/g creatinine, range = 1.4–25.6 μg/g creatinine) were markedly higher than levels found in subjects from the upper-Strickland area (mean hair mercury = 0.75 μg/g, mean urinary mercury = 0.48 μg/g creatinine). Mercury intake of the fish eaters, estimated from mercury concentrations found in fish and from the observed amounts of fish consumed, was approximately 73 μg/d. Hair and urinary mercury concentrations were correlated significantly (r = .59), indicating that urinary mercury excretion was elevated because fish consumption was very high.

51 citations

Journal ArticleDOI
TL;DR: The hair-organ relationship of mercury concentration was investigated in 46 autopsy samples in Tokyo, Japan and evidenced that the hair organic mercury value was the major explanatory variable for the organ total mercury or organ methyl mercury value in all the organs.
Abstract: The hair-organ relationship of mercury concentration was investigated in 46 autopsy samples in Tokyo, Japan. Hair mercury levels were highly significantly correlated with organ Hg levels in the cerebrum, cerebellum, heart, spleen, liver, kidney cortex, and kidney medulla, when the total mercury or methyl mercury value in the organ was compared with the hair total mercury or organic mercury, respectively. When the inorganic mercury value was tested, significant correlations remained, with weaker coefficients in all the organs but the spleen. Stepwise multiple regression analysis evidenced that the hair organic mercury value was the major explanatory variable for the organ total mercury or organ methyl mercury value in all the organs. To explain the organ inorganic mercury value, the hair organic mercury value was the major variable for the cerebrum and kidney (both cortex and medulla), the hair inorganic mercury value was the major variable for the cerebellum and heart, and the hair phosphorous and hair organic mercury were the major variables for the liver; no explanatory variable existed for the spleen. Auxiliary explanatory variables accounted for the organ total mercury and inorganic mercury levels, among which the hair selenium value was conspicuous with negative regression coefficients.

43 citations

Journal ArticleDOI
TL;DR: Samples from the Kofun era showed a completely different composition from those of other periods, i.e. they had the highest concentrations of Cd, Zn and Mg, and the lowest concentrations of Cu, K, Ni and Sr.

41 citations

Journal ArticleDOI
TL;DR: The most important purchased plant foods were wheat flour and rice, which have gradually replaced the local plant staples, mainly sago flour, and the ratio of protein per energy unit of wheat flour is twice as high as that of tubers and more than 15 times as highAs that ofSago flour.
Abstract: Seventy‐eight foods (70 locally exploited and 8 purchased) consumed by the Gidra in lowland Papua were sampled and their nutrient compositions and metal concentrations were determined. Because local food samples were collected in the state in which they were normally eaten by the villagers, the water content of several of our samples, especially of sago flour, was much greater than that in the literature. The variation of protein and energy content in nine samples of banana (genus Musa) was greater than that in six samples of tuberous crops belonging to four different genera. The most important purchased plant foods were wheat flour and rice, which have gradually replaced the local plant staples, mainly sago flour. The ratio of protein per energy unit of wheat flour is twice as high as that of tubers and more than 15 times as high as that of sago flour.

35 citations


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01 Jan 1980
TL;DR: In this article, the influence of diet on the distribution of nitrogen isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant nitrogen isotopic composition and found that the variability of the relationship between the δ^(15)N values of animals and their diets is greater for different individuals raised on the same diet than for the same species raised on different diets.
Abstract: The influence of diet on the distribution of nitrogen isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant nitrogen isotopic composition. The isotopic composition of the nitrogen in an animal reflects the nitrogen isotopic composition of its diet. The δ^(15)N values of the whole bodies of animals are usually more positive than those of their diets. Different individuals of a species raised on the same diet can have significantly different δ^(15)N values. The variability of the relationship between the δ^(15)N values of animals and their diets is greater for different species raised on the same diet than for the same species raised on different diets. Different tissues of mice are also enriched in ^(15)N relative to the diet, with the difference between the δ^(15)N values of a tissue and the diet depending on both the kind of tissue and the diet involved. The δ^(15)N values of collagen and chitin, biochemical components that are often preserved in fossil animal remains, are also related to the δ^(15)N value of the diet. The dependence of the δ^(15)N values of whole animals and their tissues and biochemical components on the δ^(15)N value of diet indicates that the isotopic composition of animal nitrogen can be used to obtain information about an animal's diet if its potential food sources had different δ^(15)N values. The nitrogen isotopic method of dietary analysis probably can be used to estimate the relative use of legumes vs non-legumes or of aquatic vs terrestrial organisms as food sources for extant and fossil animals. However, the method probably will not be applicable in those modern ecosystems in which the use of chemical fertilizers has influenced the distribution of nitrogen isotopes in food sources. The isotopic method of dietary analysis was used to reconstruct changes in the diet of the human population that occupied the Tehuacan Valley of Mexico over a 7000 yr span. Variations in the δ^(15)C and δ^(15)N values of bone collagen suggest that C_4 and/or CAM plants (presumably mostly corn) and legumes (presumably mostly beans) were introduced into the diet much earlier than suggested by conventional archaeological analysis.

5,548 citations

Journal ArticleDOI
TL;DR: The human T-cell leukemia virus type 1 (HTLV-1), identified as the first human oncogenic retrovirus 30 years ago, is not an ubiquitous virus, with clusters of high endemicity located often nearby areas where the virus is nearly absent.
Abstract: The human T-cell leukemia virus type 1 (HTLV-1), identified as the first human oncogenic retrovirus 30 years ago, is not an ubiquitous virus. HTLV-1 is present throughout the world, with clusters of high endemicity located often nearby areas where the virus is nearly absent. The main HTLV-1 highly endemic regions are the Southwestern part of Japan, sub-Saharan Africa and South America, the Caribbean area and foci in Middle East and Australo-Melanesia. The origin of this puzzling geographical or rather ethnic repartition is probably linked to a founder effect in some groups with the persistence of a high viral transmission rate. Despite different socio-economic and cultural environments, the HTLV-1 prevalence increases gradually with age, especially among women in all highly endemic areas. The three modes of HTLV-1 transmission are mother to child, sexual transmission and transmission with contaminated blood products. Twenty years ago, de The and Bomford estimated the total number of HTLV-1 carriers to be 10-20 millions people. At that time, large regions had not been investigated, few population-based studies were available and the assays used for HTLV-1 serology were not enough specific. Despite the fact that there is still a lot of data lacking in large areas of the world and that most of the HTLV-1 studies concern only blood donors, pregnant women or different selected patients or high-risk groups, we shall try based on the most recent data, to revisit the world distribution and the estimates of the number of HTLV-1 infected persons. Our best estimates range from 5-10 millions HTLV-1 infected individuals. However, these results were based on approximately 1.5 billion of individuals originating from known endemic areas with reliable available epidemiological data. Correct estimates in other highly populated regions such as China, India, the Maghreb and East Africa is currently not possible, thus, the current number of HTLV-1 carriers is very probably much higher.

1,057 citations

Journal ArticleDOI
TL;DR: The results suggest that the delta(15)N signatures of nitrogen at the base of the food chain will provide a useful tool in the assessment of anthropogenic nutrient inputs.
Abstract: Recent studies have shown the utility of delta(15)N to model trophic structure and contaminant bioaccumulation in aquatic food webs. However, cross-system comparisons in delta(15)N can be complicated by differences in delta(15)N at the base of the food chain. Such baseline variation in delta(15)N is difficult to resolve using plankton because of the large temporal variability in the delta(15)N of small organisms that have fast nitrogen turnover. Comparisons using large primary consumers, which have stable tissue isotopic signatures because of their slower nitrogen turnover, show that delta(15)N increases markedly with the human population density in the lake watershed. This shift in delta(15)N likely reflects the high delta(15)N of human sewage. Correcting for this baseline variation in delta(15)N, we report that, contrary to expectations based on previous food-web analysis, the food chains leading up to fish varied by about only one trophic level among the 40 lakes studied. Our results also suggest that the delta(15)N signatures of nitrogen at the base of the food chain will provide a useful tool in the assessment of anthropogenic nutrient inputs.

1,029 citations

Journal ArticleDOI
TL;DR: Low Se status is likely to contribute to morbidity and mortality due to infectious as well as chronic diseases, and increasing Se intakes in all parts of the world can be expected to reduce cancer rates.
Abstract: Food systems need to produce enough of the essential trace element Se to provide regular adult intakes of at least 40 microg/d to support the maximal expression of the Se enzymes, and perhaps as much as 300 microg/d to reduce risks of cancer. Deprivation of Se is associated with impairments in antioxidant protection, redox regulation and energy production as consequences of suboptimal expression of one or more of the Se-containing enzymes. These impairments may not cause deficiency signs in the classical sense, but instead contribute to health problems caused by physiological and environmental oxidative stresses and infections. At the same time, supranutritional intakes of Se, i.e. intakes greater than those required for selenocysteine enzyme expression, appear to reduce cancer risk. The lower, nutritional, level is greater than the typical intakes of many people in several parts of the world, and few populations have intakes approaching the latter, supranutritional, level. Accordingly, low Se status is likely to contribute to morbidity and mortality due to infectious as well as chronic diseases, and increasing Se intakes in all parts of the world can be expected to reduce cancer rates.

977 citations

Journal ArticleDOI
TL;DR: In this article, a simple linear regression between log10 transformed mercury (Hg) concentration and stable nitrogen isotope values (δ15N), hereafter called trophic magnification slope (TMS), was used to represent the overall degree of Hg biomagnification.
Abstract: The slope of the simple linear regression between log10 transformed mercury (Hg) concentration and stable nitrogen isotope values (δ15N), hereafter called trophic magnification slope (TMS), from several trophic levels in a food web can represent the overall degree of Hg biomagnification. We compiled data from 69 studies that determined total Hg (THg) or methyl Hg (MeHg) TMS values in 205 aquatic food webs worldwide. Hg TMS values were compared against physicochemical and biological factors hypothesized to affect Hg biomagnification in aquatic systems. Food webs ranged across 1.7 ± 0.7 (mean ± SD) and 1.8 ± 0.8 trophic levels (calculated using δ15N from baseline to top predator) for THg and MeHg, respectively. The average trophic level (based on δ15N) of the upper-trophic-level organisms in the food web was 3.7 ± 0.8 and 3.8 ± 0.8 for THg and MeHg food webs, respectively. For MeHg, the mean TMS value was 0.24 ± 0.08 but varied from 0.08 to 0.53 and was, on average, 1.5 times higher than that for THg with a...

634 citations