Tsukasa Inaoka

Stable carbon and nitrogen isotopic composition of diet and hair of Gidra-speaking Papuans

The carbon and nitrogen stable isotopic composition of the scalp hair and diet of Gidra-speaking people in four villages in Papua New Guinea is presented. The isotopic composition of hair was measured, while that of the diet was estimated from food consumption survey data and the measured isotopic composition and protein and carbohydrate contents of food items. The average isotopic ratios of the hair samples and of the diet varied among the four study villages, which were selected because of their diverse ecological settings. Comparison was made between hair and calculated dietary isotopic compositions. Two of the four diet-hair enrichment values obtained for 13C (+1.8 and 2.2%) were similar to those previously reported (1.4-2.0%), but the other two values (3.7 and 4.8%) were greater than in earlier reports. 15N enrichment was systematically greater (by 1.0%) than reported values (4.3%) except for one village, where a much greater enrichment (6.9%) was found. The factors potentially relevant to these deviations are discussed. Possible errors in estimating the dietary isotopic composition and minor modifications of dietary habits revealed by food consumption surveys could explain most of the discrepancies. However, the great enrichment of 15N found in one of the villages remains unexplained.

Correlations of pedometer readings with energy expenditure in workers during free-living daily activities

SummaryIn a total of 23 subjects consisting of 10 clerical and 13 assembly workers in a factory, the pedometer readings during a day of free-living activity were analyzed for the relation with energy expenditure as determined by the simultaneously recorded 24-hour heart rate. The 24-hour energy expenditures in the clerical and assembly workers were 9515 kJ (2274 kcal) and 9698 kJ (2318 kcal) respectively. The whole day readings of the pedometer for all the subjects moderately correlated (r=0.438,p<0.05) with the net energy cost (NEC) as determined by subtracting the sleeping metabolic cost from the energy expenditure (clerical workers:r=0.781,p<0.01; assembly workers:r=0.188,p>0.05). The correlation analysis of the pedometer readings with the NEC in three activity phases in a day (work, commuting and staying at home), showed that the extent of the relationship differed by job types and activity phases. The best correlation was obtained during commuting in both of the job types (clerical workers:r=0.843,p<0.01; assembly workers:r=0.743,p<0.01). During work, a quite strong correlation (r=0.889,p<0.01) was obtained with the clerical workers but not with the assembly workers. No significant correlations were found in the data while the subjects were at home. The capacity of the pedometer to detect the impacts of body movements, and the characteristics of activity, are responsible for the differences in correlation. The limitations of the pedometer suggested in the present study must be taken into account if the device is to be used for measuring physical activity. A particular advantage of the device appears in its use for a sedentary population without regular srenuous exercise or static contractions.

Mercury concentration correlates with the nitrogen stable isotope ratio in the animal food of papuans

The relationships among element concentrations (Na, Mg, Al, P, K, Ca, Cr, Fe, Mn, Cu, Zn, Sr, total Hg, organic Hg, inorganic Hg, Pb) and stable carbon and nitrogen isotope ratios (13C/12C and 15N/14N) in animals consumed by the people called Gidra, who inhabit the lowland of Papua New Guinea, were examined. Animals analyzed included mammal, bird, fish, shellfish, reptile, crustacean, and insect. Highly significantly positive correlations were observed between total Hg concentrations and 15N/14N (r = 0.796), between organic Hg concentrations and 15N/14N (r = 0.781), and between inorganic Hg concentrations and 15N/14N (r = 0.739). This was interpreted to indicate that Hg was an element which accumulates in animals along the food chain. Based on the regression function of Hg on delta 15N, the bioconcentration factor for total, organic, and inorganic Hg was estimated to be 5.

Diversity and change of food consumption and nutrient intake among the Gidra in Lowland Papua

Food consumption and nutrient intake of the Gidra in lowland Papua, who number 1,850 and inhabit 13 villages, were analyzed by compilation of five two‐week (or twelve‐day) records, in a single village in 1971 and in four different villages (including the above village) in 1981. The nutrient intake of the Gidra varied both over time and among the villages. Difference in food consumption patterns included different proportions of plant staples such as sago flour, garden crops and purchased cereals. The animal protein sources, mainly game and fish, also markedly varied among the villages. These differences in food consumption were related to environmental conditions such as the fauna and flora in the environment of each village and to the degree of modernization as reflected in ability to purchase foods not locally grown. The causal relationship between ecological (environmental and cultural) conditions and food and nutrition is discussed, and a schematic model for this relationship is presented.

Occupational dermatoses among fibreglass-reinforced plastics factory workers

Fibreglass‐reinforced plastics (FRP) factory workers are at high risk of developing occupational dermatoses because of their exposure to many chemicals used in the manufacture of plastics as well as to glass fibre or dust. Patch tests were carried out on 29 workers involved in FRP manufacturing processes where unsaturated polyester (UP) resin was used, to investigate the causes of their skin problems. Of the 22 workers who reported experiencing skin problems, 16 showed positive results to at least 1 chemical, including 6 cases of multiple sensitivity. 2 showed positive reactions to UP base resin, 6 to cobalt chloride, 5 to benzoyl peroxide (BPO), 4 to methyl ethyl ketone peroxide (MEKPO), 2 to para‐tertiary butyl catechol (PTBC), 1 to styrene and 1 to formaldehyde. After taking into account their exposures and reported causes by questionnaires and their patch test results, 7 cases were diagnosed as allergic contact dermatitis (ACD) due to chemicals, 3 as irritant contact dermatitis (ICD) due to chemicals, and 3 as dermatitis due to mechanical irritation (MI) from glass fibre or dust, as well as 9 as ACD and/or MI. 18 of the total of 29 subjects (62.1%), including 2 workers without a history of skin problems, were sensitized to at least 1 chemical. Cobalt, peroxides, PTBC and UP base resin were the common causes of ACD.

Carbon and nitrogen isotopic characterization for Papua New Guinea foods

Stable carbon and nitrogen isotope ratios of the animal and plant food of the Gidra, who inhabit lowland Papua New Guinea and subsist mainly on hunting, gathering and horticulture, were measured to characterize the nutritional input of carbon and nitrogen of the Gidra. All the staple plant foods of the Gidra, such as sago and tuberous crops, were classified as C3 plants from their 13C/12C ratios (δ13C). The δ13C of the terrestrial mammals varied to a considerable extent (—11 to —26.5 per mil); the highest value was observed for a species of wallaby inhabiting savanna grassland while two other species of wallabies inhabiting woodland were —25.3 and —22.8 per mil. The δ13C of the aquatic animals was distinctive between marine (—17.0 to —7.1 per mil) and freshwater (—34.6 to —24.0 per mil) groups. The δ15N of the fishes and reptiles were generally higher than terrestrial animals. Major foods of the Gidra were isotopically divided into 5 groups: C3 plant, C3 plant feeder, C4 plant feeder, marine animal and fr...

Allergic contact dermatitis in shiitake (Lentinus edodes (Berk) Sing) growers

A 42‐year‐old female shiitake grower was investigated to clarify the etiology of skin lesions which developed during the planting Of shiitake hyphae into bed logs. She complained of repeated eczematous skin lesions during the planting season, from March to July, for 10 years. She handled 7,000 pieces of small conic Mucks made of beech, with shiitake hyphae attached in their surface, per day, and 300,000 pieces altogether per season. She was positive on patch testing with extracts of shiitake hyphae. In contrast, female shiitake growers with skin lesions associated with work other than planting, and without skin lesions, were negative on patch testing to she hyphae. Moderate allergenicity was observed to extracts of shiitake hyphae in a guinea pig maximization test. These findings indicated the etiology of skin lesions in shiitake growers to be allergic contact dermatitis induced by shiitake hyphae.

Element intake of the Gidra in lowland Papua: Inter‐village variation and the comparison with contemporary levels in developed countries

Intake of 17 elements (Na, Mg, Al, P, K, Ca, V, Cr, Mn, Fe, Ni, Cu, Zn Sr, Cd, Hg and Pb) was estimated in four villages of the Gidra in lowland Papua New Guinea. Among these elements, inter‐village variation of intake was relatively large for Na, Al, V, Fe, Ni, Cd, Hg and Pb. The variation was attributed to the different concentrations in foods and drinking water, and the differences in food consumption by different villages. Compared to the intake levels reported in Japan, the USA and European countries, Na, Ca, Ni, Cd and Pb intake in the Gidra was low. Low Na intake was principally caused by low consumption of salt. Low Na and Ca intakes were attributed to the low levels of consumption of animal foods. On the other hand, Mg, Al, K, Mn, Fe and Sr intake levels in the Gidra were high. In particular, extremely high Fe intake was attributed to region‐specific foods such as sago, wild seeds and shellfish.

Allergic contact dermatitis due to methyl ethyl ketone peroxide, cobalt naphthenate and acrylates in the manufacture of fibreglass‐reinforced plastics

A 64-year-old man who had been a part-time worker in a fibreglass-reinforced plastics (FRP) factory producing gutter covers etc. developed severe acute hand dermatitis 6 years into his employment. He was involved in the assembly process and had had no previous skin problems. Before the onset, he had not worn protective gloves either when using resin, hardener and accelerator to mend flaws in moulded FRP products, or when using acrylate glue to assemble the FRP. The chemical composition of the resin was unsaturated polyester resin (UP) and the main ingredients of the hardener and accelerator were methyl ethyl ketone peroxide (MEK peroxide) and cobalt naphthenate, respectively. The glue was the product of a mixture of acrylates. Two months’ treatment and sick leave cured the dermatitis. He returned to work in the same FRP manufacturing process as before, but started wearing natural rubber latex (NRL) gloves with inner thin cotton gloves. Nine months later, with careful use of gloves, he showed only minor recurrence (scaling on the fingertips). Patch tests showed positive results to MEK peroxide in the hardener, cobalt naphthenate in the accelerator and 2-hydroxyethyl methacrylate and methyl methacrylate in the acrylate glue (Table 1).

Cardiovascular risk factors of migrants in Port Moresby from the highlands and island villages, Papua New Guinea.

This study examined cardiovascular disease (CVD) risk factors, i.e., obesity, blood pressures, and serum lipoproteins and apoproteins, in relation to sociocultural characteristics in two rural–urban migrant populations (n = 173 adult males and females) in Port Moresby, the capital of Papua New Guinea. Tari migrants from the highlands and Balopa migrants from the islands differ genetically. More importantly, the lifestyle of the latter is more Westernized than that of the former in both Port Moresby and their homelands. The results demonstrate that CVD risk factors vary markedly among the origin/sex groups and that the length of stay in Port Moresby on CVD risk factors was significant only in Balopa males, most of whom had professional or skilled full‐time jobs and were considered to have more stress. This study identified different CVD risk factors in the migrant groups: obesity or fatness for the Balopa migrants, and serum lipoproteins and apoproteins, particularly lipoprotein(a), for the Tari migrants. Am. J. Hum. Biol. 12:655–664, 2000.