Establishment of mesenchymal cell line derived from human developing odontoma.

OBJECTIVES: An odontoma, which shows proliferating odontogenic epithelium and mesenchymal tissue, is one of the most common odontogenic tumors encountered. These are commonly found in tooth-bearing regions, although the etiology remains unknown. There are no previous reports of an established line of immortalized human odontoma cells. METHODS: Using odontoma fragments obtained from a girl treated at our department, we established an immortalized human odontoma cell line and investigated cell morphology, dynamic proliferation, the presence of contamination, and karyotype. Moreover, cell characterization was examined using osteogenic and odontogenic markers. RESULTS: We successfully established a mesenchymal odontoma cell (mOd cells). The cells were found to be fibroblastic and had a high level of telomerase activity. Cell growth was confirmed after more than 200 population doublings without significant growth retardation. mOd cells expressed mRNA for differentiation markers, including collagen type I (COLI), alkaline phosphatase, bone sialoprotein, osteopontin, osteocalcin, cementum-derived protein (CP-23), dentin sialophosphoprotein (DSPP), and distal-less homeobox 3 (DLX3), as well as bone morphogenetic proteins (BMPs). In addition, they showed a high level of calcified nodule formation activity in vitro. CONCLUSIONS: We successfully established a cell line that may be useful for investigating the mechanisms of normal odontogenesis as well as characteristics of odontoma tumors.

Regulation of CXCL9/10/11 in oral keratinocytes and fibroblasts.

Th1 and Th2 cytokines such as interferon-gamma (IFN-gamma ) , tumor necrosis factor- alpha (TNF-alpha ), and IL-4 are expressed in T-cell-mediated inflammation in the oral cavity. We tested the hypothesis that those cytokines may act on CXCR3-agonistic chemokines, T-cell recruiting factors, and on neighboring cells, including oral keratinocytes and fibroblasts. Human immortalized oral keratinocytes (RT7) and fibroblasts (GT1) after 24-hour stimulation with IFN-gamma showed increased mRNA levels of CXCL9 (600- and 700-fold), CXCL10 (10,000- and 150-fold), and CXCL11 (5000- and 300-fold), respectively. In contrast, TNF-alpha caused an increase in CXCL9 (300-fold), CXCL10 (2000-fold), and CXCL11 (2000-fold) mRNA levels in GT1, but not RT7 cells, at 24 hrs. IL-4 reinforced the promotion of CXCL9, CXCL10, and CXCL11 expression by IFN-gamma in RT7 cells, whereas IL-4 inhibited the increased levels by IFN-gamma and TNF-alpha in GT1 cells. Thus, IFN-gamma , TNF-alpha , and IL-4 appear cooperatively to regulate CXCR3-agonistic chemokines in oral keratinocytes and fibroblasts in T-cell-mediated oral inflammation sites.

Gender-related difference, geographical variation and time trend in dietary cadmium intake in Japan.

OBJECTIVES: The present analysis was initiated to examine possible gender-dependency, geographic variation, and time-dependent changes in dietary intake of cadmium (Cd-F) among general populations in Cd-non-polluted areas in Japan. The role of rice as Cd-F source was also within the scope. METHODS: Two databases on Cd and nutritional analyses were re-visited. Both databases were established through collection of 24-h food duplicate portion samples from residents in areas with no known Cd pollution, and contained information on Cd and energy contents in the duplicate portion, together with daily rice consumption, the gender, the age and the location of the residence of each sample donor. The first and the second databases were established through surveys in the years around 1980 on 564 cases and around 1995 on 702 cases, respectively. The two databases were combined for evaluation by multiple regression (MRA) and other analyses. RESULTS: The analyses showed that men tended to take more Cd than women, more clearly so in the 1980 survey than in the 1995 survey. When Cd-F in the 1995 survey was compared with that in the 1980 survey, a substantial decrease was observed, e.g. by 30% (from 37.5 to 26.2 microg/day) in case of women. Cd-F values varied subject to the survey sites in a wide range (e.g. from 20 to 86 microg/day among women in the 1980 survey). In MRA with Cd-F as a dependent variable and survey sites and food intake factors (e.g. rice and energy intakes) as independent variables, the survey sites could explain more than 53% and 35% of total variation in Cd-F in the 1980 and 1995 surveys, respectively. Rice consumption was also influential to Cd-F in both surveys with partial correlation coefficients of 0.36 and 0.21, respectively, the influence being stronger in the 1980 survey than in the 1995 survey. A significant correlation was detected between the 1980 and 1995 survey results both in Cd-F and in rice consumption. CONCLUSION: Geographic and gender-related differences, and time-dependent decrease in dietary Cd intake in Japan were detected through analyses of food duplicate-based databases. The leading role of rice as dietary Cd source was also observed.

Methyl isobutyl ketone and methyl ethyl ketone in urine as biological markers of occupational exposure to these solvents at low levels.

OBJECTIVE: To examine whether unmetabolized methyl isobutyl ketone in urine is a useful marker of low-level occupational exposure to this ketone solvent, as is the case for methyl ethyl ketone. METHODS: The study was conducted in the second half of a working week. In total, 27 furniture-making workers (19 men and eight women) and 11 non-exposed controls (six men and five women) volunteered to participate in the study. Time-weighted average (TWA; 8-h) concentration of vapors of several solvents in air, including methyl isobutyl ketone (MIBK-A) and methyl ethyl ketone (MEK-A) was monitored by diffusive sampling. Urine samples collected at the end of the shift were subjected to head-space gas chromatography (GC) analysis for the unmetabolized solvents (i.e., MIBK-U and MEK-U). The relationship between the concentration of the solvent vapor and the corresponding solvent level in urine was examined by simple as well as multiple regression analysis. RESULTS: The exposures to MIBK and MEK were well below the current occupational exposure limit levels, but the maximum levels of exposure to toluene and ethylbenzene were around the corresponding exposure limit. The correlation of the TWA concentration of the solvent in air with the concentration of the corresponding solvent in the end-of-shift urine sample was significant both for MIBK and for MEK, and the correlation coefficient was larger for MIBK than for MEK. The slope in the exposure-excretion regression line was almost twice as steep for MEK than for MIBK, possibly due to the difference in water solubility. Approximately 0.12% of MIBK absorbed in the lungs will be excreted into urine, whereas the yield for MEK was somewhat higher (0.19%). CONCLUSION: MIBK in urine is a good marker of exposure to MIBK, as in the case of MEK in urine for MEK exposure.

Comparison of urinary bromide levels among people in East Asia, and the effects of dietary intakes of cereals and marine products.

Groups of people with no occupational exposure to Br-containing chemicals (29-54 year old, mostly women) in Japan, China and Korea, respectively, offered spot urine samples. Those in China and Korea offered 24 h duplicates of foods of the day. Urine samples were analyzed for Br by ECD-gas chromatography (ECD-GC) after derivatization to methyl bromide, and the Br-U was adjusted for a specific gravity of 1.016. Food intake data were based on national statistics and supplemented by the food duplicate data. Mean Br-U was 5.4 and 6.5 mg/l for Japanese men and women, respectively. Mean levels were in a range of 1.8-2.8 mg/l for four groups of Chinese, and 8-12 mg/l for the four groups of women in Korea. Br-U levels among Korean women were close levels reported for occupational exposure to 1- or 2-bromopropane, or methyl bromide. Regression analyses showed that Br-U levels were influenced by the intake of marine products (such as sea algae, sea fish and shellfish) and fruits, and inversely relate to intakes of cereals and potato.

Toluene, xylenes and xylene isomers in urine as biological indicators of low-level exposure to each solvent; a comparative study.

OBJECTIVE: To examine if xylenes and xylene isomers in end-of-shift urine are good biological indicators of low-level exposure to each solvent, similarly to toluene in urine. METHODS: The study was conducted in the latter half of a working week. Furniture makers, 86 subjects in total (76 men and ten women), participated in the study in combination with 11 non-exposed subjects. Time-weighted average (8-h TWA) exposures to mixtures of toluene (TOL-A), xylenes (XYLs-A), ethylbenzene (EB-A), acetone (ACE-A) etc. were monitored with diffusive samplers for lipophilic and hydrophilic solvents, respectively. Urine samples (i.e., TOL-U, XYLs-U, EB-U, ACE-U, etc.) were collected at the end of the shift and subjected to head-space gas chromatography analysis for each solvent. The exposure-excretion relationship was examined by simple as well as multiple regression analysis. RESULTS: The exposures to TOL and XYLs were around or below current occupational exposure limit levels. The exposures to other solvents [i.e., ACE, EB, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), etc.] were at substantially lower levels. The correlation of the TWA solvent exposure concentration with the concentration of the corresponding solvent in the end-of-shift urine sample was close for TOL, and also almost equally close in the case of XYLs and each of the three XYL isomers. Whereas the slope of the regression line for XYLs was significantly less steep than that for TOL when compared on an equi-molar basis, there was no difference among the three XYL isomers. No confounding effects of age, sex and co-exposure to other solvents were detected. The observation confirms previous reports that TOL-U is a good marker of TOL vapor exposure, indicates that XYL-U is also a reliable marker of exposure to vapors of XYLs or any of the three XYL isomers, and suggests that estimation of exposure to vapors of XYLs (i.e., three isomers in combination) is possible by the determination of one of the XYL isomers in urine, once the proportion of the isomers in air is known. Possible association of water solubility with solvent levels in urine is discussed. CONCLUSIONS: Biological monitoring of exposure by means of analysis of end-of-shift urine for mother solvent is possible, not only in the case of TOL as previously reported, but also in cases of XYLs, either for three isomers in combination or separately.

Estimation of nutrient intake by the new version of Japanese food composition tables in comparison with that by the previous version.

This study was initiated to examine if the revision of the food composition tables from the 4th version to the 5th version has induced any substantial changes in nutrient intake estimation, and if so, in which nutrient item and to what extent. For this purpose, 24-hour duplicates of food samples were collected in 1996 to 1998 from 71 girl university students, together with food menus of the day. The nutrients in the duplicates were estimated by use of the 4th and the 5th version food composition tables in parallel, with supplements of other databases. The results of the estimation with the two databases were compared by Student's paired t-test. Compared with the results with the 4th version, the estimation utilizing the 5th version gave 3 to 8% increases in intakes of major nutrients including energy (except for protein), a 20% increase in vitamin A, and decreases in iron (-13%) and NaCl (-3%), whereas there were only small or essentially no changes in other minerals and vitamins. The largest increment in energy through the re-calculation came from the cereals (especially rice), and it was meats for the increment in lipid intake. The increment in vitamin A with the 5th version is primarily due to the re-evaluation of fruits and vegetables. The present observation suggests that care should be practiced in examining secular trends in nutrition when the basis of estimation is shifted from one database of the 4th version of food composition tables to another of the 5th version. Further study of a larger scale is apparently warranted to confirm the conclusions.

Optically active antifungal azoles. XIII. Synthesis of stereoisomers and metabolites of 1-[(1R,2R)-2-(2,4-difluorophenyl)-2-hydroxy-1-methyl-3-(1H-1,2,4-triazol-1-yl)propyl]-3-[4-(1H-1-tetrazolyl)phenyl]-2-imidazolidinone (TAK-456).

1-[(1R,2R)-2-(2,4-Difluorophenyl)-2-hydroxy-1-methyl-3-(1H-1,2,4-triazol-1-yl)propyl]-3-[4-(1H-1-tetrazolyl)phenyl]-2-imidazolidinone [(1R,2R)-1: TAK-456] is a new antifungal agent selected as a candidate for clinical trials. The three stereoisomers [(1S,2R)-, (1S,2S)- and (1R,2S)-1] of this compound were prepared as authentic samples to determine the enantiomeric and diastereomeric purity of TAK-456 as well as to compare their in vitro antifungal activity. Pharmacokinetic studies of TAK-456 using rats identified the existence of metabolites in the liver homogenate. The structures of the major metabolites were assigned as 4-hydroxy-2-imidazolidinone (3) and/or 5-hydroxy-2-imidazolidinone (4), based on HPLC and LC/MS/MS analyses. These hydroxylated compounds, 3 and 4, were prepared by reduction of the corresponding imidazolidinediones, 11 and 12, and confirmed to be identical to the metabolites by HPLC. In vitro antifungal activities of the three stereoisomers and the synthesized metabolites were considerably weaker than TAK-456.

Prevalence of hepatitis B and C virus infection among women in Jeju Island, Republic of Korea.

Hepatitis B and C virus infection prevalence was investigated in the Island of Jeju (formerly Cheju), the Republic of Korea, by means of a small-scale sero-epidemiological survey in 2000. Adult women in the city of Jeju (the provincial capital) and two fishing-farming villages A and B were invited to offer venous blood samples for immunological examination for infection markers of two virus and serum biochemistry for liver function. In practice, 66 married women (33, 16 and 17 women from the city, Village A and Village B, respectively) volunteered. Sera were separated on site and were assayed for HBsAg, anti-HBs, anti-HBc, and anti-HCV positivities and liver function markers including AST, ALT and gamma-GTP. The serum assay showed that the prevalence of HbsAg+ or anti-HCV+ cases was low (5 and 2%, respectively), whereas that of anti-HBs+ and anti-HBc+ cases were high (71 and 62%) so that the over-all HBV positivity was 82%. There were essentially no urban-rural difference or age-dependent changes in the positivity. Comparison with the prevalence reported in literature shows that prevalence of HBsAg+ and anti-HCV+ is in general agreement with the values reported for the populations in general, but HBV+ prevalence might be somewhat higher than the levels reported for the general populations.

Urinary bromide levels probably dependent to intake of foods such as sea algae.

The purpose of the present study is to examine if the bromide (Br) level in urine (Br-U) varies substantially among adult general populations of either sex or of different dietary habits. For this purpose, morning spot urine samples (about 50 per group) were collected from six groups of people, i.e., one group each of men and women in a city in Japan (thus two groups in Japan) and one group each of women in two urban and two rural areas in central and northeast China (four groups in China). The samples were analyzed for Br by ECD-gas chromatography after derivatization to methyl bromide. Br-U essentially followed a normal distribution. Whereas there was only a marginal difference in Br-U between men (7.7 +/- 2.5 mg/L as an arithmetic mean and arithmetic standard deviation) and women (8.1 +/- 2.9 mg/L) in Japan, and no difference between the urban (2.3 +/- 0.8 mg/L) and rural women (2.6 +/- 1.1 mg/L) in China, the difference between Japanese (8.1 +/- 2.9 mg/L) and Chinese women (2.3 +/- 0.8 mg/L for two cities and 2.6 +/- 1.1 mg/L for two villages) was substantial. A literature survey suggested variation in dietary habits, especially that in sea algae intake, is a possible factor affecting the observed difference in Br-U between the two ethnic groups. Contribution of Br in cereals after fumigation with, e.g., methyl bromide, was also thought to be possible. The implication of difference in background Br-U levels is discussed in relation to biological monitoring of exposure to Br-containing industrial chemicals, such as 1- and 2-bromopropane.

Dietary selenium intake of Chinese adult women in the 1990s.

To assess the levels of daily dietary intake of selenium (Se) among the general Chinese population, a series of field surveys were conducted in the 1990s. Samples of 24-h duplicates of foods were collected from 500 participants (300 in 6 cities and 200 from 4 villages). Se levels were determined by microwave digestion followed by inductively coupled plasma-mass spectrometry (ICP-MS), and the measurements were compared with FCT (Food Composition Tables)-based estimates. The average daily intake of Se was 69.2 lg/d (79.9 and 53.1 microg/d in urban and rural areas, respectively) by instrumental determination and 35.1 microg/d (36.7 and 32.7 microg/d) by FCT-based estimation. As the distribution of Se should be uneven within China, the FCT-based estimation is of a limited value and the ICP-MS determination of Se is more accurate and reliable when evaluating the nutritional status of local people. Taking ICP-MS-based values, Se intakes were lower in rural areas than in urban areas, and the intakes of about half of the people in rural areas were less than the Recommended Daily Allowance (RDA) in China of 50 microg/d. The low intake might be resulted from difference in the types of food consumed. Thus, the dietary intake of Se basically meets the recommended RDA in most of urban areas, but insufficiency may be still a nutritional and public health problem in some rural areas.

Experiences on persistent organic pollutants under the Law concerning the Examination and Regulation of Manufacture, etc. of Chemical Substances, Japan, with references to biodegradation and bioaccumulation.

OBJECTIVES: The purpose of this report is to outline current regulations to control chemical environmental pollution in Japan, with special references to internationally defined 12 persistent organic pollutants (POPs). MATERIALS: Law concerning the Examination and Regulation of Manufacture, etc. of Chemical Substances [(LERCS); enacted in 1973] and related administrative activities of monitoring of the environment in Japan. RESULTS: Among the existing chemicals identified by the 1972 Chemicals Inventory, LERCS designates aldrin, chlordanes, DDT, dieldrin, endrin, HCB, PCBs, poly(Cln; n = 3 or more)-chlorinated naphthalene (PCNs) and bis(tributyltin) oxide (TBTO) as Class 1 specified chemical substances which are under strict regulation, such as prohibition of production, import, or use in principle. In addition LERCS designates 23 Class 2 specified chemical substances (including 13 tributyltin and seven triphenyltin compounds) for which notification of scheduled and past production, compliance with technical guidelines and compliance with labeling standards is requested. When compared with the 12 POPs, the designation covers most of them except for mirex and toxaphene, which have never been used in Japan. The regulation has been effective in reducing substantially the levels of the designated chemical substances (and therefore the 12 POPs except for dioxins and furans) in the general environment in Japan. Efforts are currently focused under a newly enacted law to reduce the emission of the two non-intentionally produced pollutants of dioxins and furans, especially from city waste incinerators, so that emission in 2002 should be 10% of that in 1997. CONCLUSION: Regulations to control chemical emissions have been effective in reducing POPs levels in the environment in Japan, and further efforts have been made under a new law to reduce the emission of dioxins, furans and co-planar PCBs.

Cadmium and lead contents in rice and other cereal products in Japan in 1998-2000.

Cereals, especially rice, are a major source of cadmium (Cd) intake for general Japanese populations. In 1998-2000, rice (polished), bread (loaf), noodle and (wheat) flour samples (4113 samples in total) were collected in 63 cities all over Japan, and analyzed for Cd by inductively-coupled plasma mass spectrometry. Another pollutant element of lead (Pb) was determined in parallel. The grand geometric mean for Cd in polished raw (uncooked) rice was 50 ng/g, whereas it was 19 ng/g for flour. The value for Pb was 2-3 ng/g in rice and flour. Calculation for daily Cd intake via rice, taking advantage of the present findings on Cd contents in rice and wheat together with administrative area-specific daily consumptions of rice and wheat showed that Cd via rice is much more than Cd via wheat and that Cd via rice is highest in an area alongside the sea of Japan among the whole country, the observation being in agreement with the results from a previous food duplicate-based field survey.

A simple HPLC method to determine urinary phenylmercapturic acid and its application to gasoline station attendants to biomonitor occupational exposure to benzene at less than 1 ppm.

The objective of this study was to establish a hand-saving method to measure phenylmercapturic acid (PMA) and to examine urinary PMA as a marker of occupational exposure to benzene at levels less than 1 ppm. A simple HPLC method was developed to analyse PMA by monitoring absorption at 195 nm of the ef? uent from an ODS-3 column with acetonitrile-methanol-perchloric acid-water as a mobile phase. The detection limit of the method was 0.2 µg l(-1) with sufficient reproducibility. The method was applied to end-of-shift urine samples from 70 gasoline station attendants exposed to up to 107 ppb benzene, and 20 non-exposed controls of both sexes. Time-weighted average (TWA) exposure to benzene was measured by diffusive sampling. A regression analysis was applied to examine the quantitative relationship between the intensity of exposure to benzene and PMA in the end-of-shift urine samples. Multiple regression analysis showed no effects of age, sex, smoking and co-exposure to toluene and xylenes on urinary PMA. There was a linear relationship between TWA benzene exposure and urinary PMA (r = 0.60-0.67, P < 0.01). Background PMA in urine of the non-exposed controls was low and scattering of PMA around the regression line was narrow so that those with 20 ppb benzene exposure can be separated from the non-exposed by urinalysis for PMA. Thus, urinary PMA is sensitive enough for biological exposure monitoring of those exposed to less than 1 ppm benzene.

Biological monitoring of occupational exposure to 1-bromopropane by means of urinalysis for 1-bromopropane and bromide ion.

The purposes of the present study are (1) to develop a sensitive analytical method to measure 1-bromopropane (1-BP) in urine, (2) to examine if 1-BP or bromide ion (Br) in urine is a useful biomarker of exposure to 1-BP, and (3) to identify the lowest 1-BP exposure concentration the method thus established can biomonitor. A factory survey was carried out on Friday, and 33 workers (all men) in cleaning and painting workshops participated; each worker was equipped with a diffusive sampler (carbon cloth KF-1500 as an adsorbent) to monitor 1-BP vapour for an 8-h shift, and offered a urine sample at the end of the shift for measurement of 1-BP and Br in urine. In addition, 10 non-exposed men offered urine samples as controls. The performance of the carbon cloth diffusive sampler was examined to confirm that the sampler is suitable for monitoring time-weighted average 1-BP vapour exposure. A head-space GC technique was employed for analysis of 1-BP in urine, whereas Br in urine was analysed by ECD-GC after derivatization to methyl bromide. The workers were exposed to vapours of seven other solvents (i.e. toluene, xylenes, ethylbenzene, acetone, etc.) in addition to 1-BP vapour; the 1-BP vapour concentration was 1.4 ppm as GM and 28 ppm as the maximum. Multiple regression analysis however showed that 1-BP was the only variable that influenced urinary 1-BP significantly. There was a close correlation between 1-BP in urine and 1-BP in air; the correlation coefficient (r) was >0.9 with a narrow variation range, and the regression line passed very close to the origin so that 2 ppm 1-BP exposure can be readily biomonitored. The correlation of Br in urine with 1-BP in air was also significant, but the r (about 0.7) was smaller than that for 1-BP, and the background Br level was also substantial (about 8 mg l(-1)). Thus, it was concluded that 1-BP in end-of-shift urine is a reliable biomarker of occupational exposure to 1-BP vapour, and that Br in urine is less reliable.

Possible metabolic interaction between hexane and other solvents co-exposed at sub-occupational exposure limit levels.

OBJECTIVE: To investigate whether metabolic interactions exist between hexane (HEX) and other solvents when co-exposed at the levels below occupational exposure limits. METHODS: Workers, 219 men in ten workshops in total, volunteered to participate in the study. They were occupationally exposed to mixtures of HEX and one or more of toluene (TOL), ethyl acetate (EA) and acetone (ACE). Time-weighted average intensity of vapor exposures was monitored by diffusive personal sampling. 'Free'- and 'total'-2,5-hexanedione (HD) levels in the end-of-shift urine samples were determined by gas chromatography (GC) before and after acid hydrolysis of urine, respectively, and expressed as observed (HDob) or after correction for creatinine concentration (HDcr) or urine specific gravity (HDsg). Possible interaction was examined by multiple regression analysis (MRA), taking either free- or total-HD as a dependent variable, and the four solvent concentrations as independent variables. RESULTS: In most cases, exposure intensity did not exceed the current occupational exposure limits even when additiveness was assumed. In addition that HEX was the most influential independent variable in all cases as expected, the MRA showed that, in cases of free-HD, ACE was also influential to HDob although weakly, but not to HDcr or HDsg. With regard to total-HD, ACE was weakly influential to HDob and HDsg, and EA also weakly to HDcr. The effect of ACE on free- or total-HD was not detected, however, when 22 men exposed only to HEX and ACE were subjected to the same analysis. Similarly, the effect of EA on total-HD was not observed among the remaining 197 men exposed to HEX, TOL and EA only. CONCLUSIONS: When the exposures were below occupational exposure limits, the free-HD levels in urine after HEX exposure will not be modified by co-exposures to TOL, EA or ACE.

Nutrient intake of adult women in Jilin Province, China, with special reference to urban-rural differences in nutrition in the Chinese continent.

OBJECTIVES: The objectives of this study were to investigate possible urban-rural differences in food intakes in Jilin province and in continental China as a whole, and to examine possible implications for nutritional status of urban and rural populations. DESIGN: Cross-sectional study. SETTING: Communities. SUBJECTS: In total, 499 adult women in six urban sites and four rural sites, 10 sites in total, including two sites in Jilin province. METHODS: A pair of surveys were conducted in September, 1999, in the provincial capital of Changchun and a farming village in Dehui county, both in Jilin province, in northeast China. Each of 50 adult women per survey site provided a 24 h duplicate food sample and a blood sample, and had an interview on health history including anthropometry and blood pressure measurement. Nutrient intakes were estimated from the food duplicates, using national food composition tables. Results from the two sites were supplemented with data from eight sites where surveys had been conducted following the same protocol, and the pooled material were subjected to analyses for possible urban-rural differences. RESULTS: The Jilin participants consumed daily, on average, about 1600 kcal energy, 44 g protein, and 60 g lipid with a lipid energy ratio (i.e. the ratio of lipid over total nutrients in terms of energy) of 33%. When nutrient intakes were compared between the urban (i.e. Changchun) and rural (Dehui) groups, urban women consumed more energy, protein (especially animal protein) and lipid than rural women. Similar examination of data from six urban and four rural sites, including the present two, showed that adult women in urban areas eat more animal protein and animal fat than their counterparts in villages, and suggested that the observation on urban rural difference in Jilin province can be extrapolated to a nationwide scale. CONCLUSIONS: Urban rural differences in nutrient intakes still persist in 1999 not only in Jilin but in other provinces, typically in the terms of intakes of animal-based foods.

Exposure of women in general populations to lead via food and air in East and Southeast Asia.

BACKGROUND: Despite increasing public concern of the possible health effects of lead (Pb) on general populations, reports on Pb levels in blood (Pb-B) and urine (Pb-B), as well as Pb intake via foods (Pb-F) for many Asian countries are scarce. The present study was initiated to elucidate the extent of non-occupational Pb exposure among general populations in East and Southeast Asia. METHODS: In 1991-1997, peripheral blood, morning spot urine and 24-hour food duplicate samples were collected from 20 to 50 non-smoking adult women in each of four cities in Southeast Asia and five cities in Mainland China, and two cities each in Japan and Korea. The samples were wet-ashed and then analyzed by inductively coupled plasma mass spectrometry for Pb-B, Pb-U and Pb-F. Measures after logarithmic conversion were subjected to ANOVA and regression analysis. RESULTS: Geometric mean values in cities in East and Southeast Asia were in ranges of 32-65 microg/L for Pb-B, 2.1-7.5 microg/g cr for Pb-Ucr, and 7-32 microg/day for Pb-F. The values for a combination of two cities of Tokyo and Kyoto, Japan (38 microg/L for Pb-B and 9.3 microg/day for Pb-F) appeared to be lower than the values for other Asian cities, and the values for all Japan (thus including both urban and rural areas) were even lower (19 microg/L for Pb-B and 7.7 microg/day for Pb-F). Comparison of Pb uptake via respiratory and dietary routes showed that Pb via dietary route accounted for 15% of the total in Manila where Pb in air was high (ca. 650 ng/m(3)), whereas it was 54% in Tokyo+Kyoto where Pb in air was low (ca. 75 ng/m(3)). CONCLUSIONS: When compared internationally, Pb-F and Pb-B in Asia in general are similar to or somewhat higher than the levels in Europe and USA, whereas the levels in Japan are probably lower than the two latter areas. In Asia, Pb-F accounted for 15-54% of all Pb sources, the percentage being variable depending on local conditions especially Pb in atmospheric air.

Monitoring of occupational exposure to tetrachloroethene by analysis for unmetabolized tetrachloroethene in blood and urine in comparison with urinalysis for trichloroacetic acid.

OBJECTIVE: The present study was initiated to examine a quantitative relationship between tetrachloroethene (TETRA) in blood and urine with TETRA in air, and to compare TETRA in blood or urine with trichloroacetic acid (TCA) in urine as exposure markers. METHODS: In total, 44 workers (exposed to TETRA during automated, continuous cloth-degreasing operations), and ten non-exposed subjects volunteered to participate in the study. The exposure to vapor was monitored by diffusive sampling. The amounts of TETRA and TCA in end-of-shift blood and urine samples were measured by either head-space gas chromatography (HS-GC) or automated methylation followed by HS-GC. The correlation was examined by regression analysis. RESULTS: The maximum time-weighted average (TWA) concentration for TETRA-exposure was 46 ppm. Regression analysis for correlation of TETRA in blood, TETRA in urine and TCA in urine, with TETRA in air, showed that the coefficient was largest for the correlation between TETRA in air and TETRA in blood. The TETRA in blood, in urine and in air correlated mutually, whereas TCA in urine correlated more closely with TETRA in blood than with TETRA in urine. The TCA values determined by colorimetry and by the GC method were very similar. The biological marker levels at a hypothetical exposure of 25 ppm TETRA were substantially higher in the present study than were the levels reported in the literature. Possible reasons are discussed. CONCLUSIONS: Blood TETRA is the best marker of occupational exposure to TETRA, being superior to the traditional marker, urinary TCA.

Blood lead level to induce significant increase in urinary delta-aminolevulinic acid level among lead-exposed workers: a statistical approach.

The present study was initiated to examine the quantitative relationship between blood lead (Pb-B) and urinary delta-aminolevulinic acid (ALA-U) among Pb-exposed workers, and to find a threshold Pb-B level to induce an increase in ALA-U. For this purpose, pairs of venous blood and spot urine samples were collected from 8,274 men and 5,856 women (14,130 workers in total) who were occupationally exposed to inorganic lead. The blood and urine samples were analyzed for Pb-B and ALA-U by atomic absorption spectrometry and colorimetry, respectively, and the correlation between pairs of measures were subjected to statistical analysis. The assumption of the 3rd degree regression for correlation gave a substantially greater correlation coefficient (0.645 for men and 0.619 for women) than 1st or 2nd degree regression, whereas only very small improvement in the coefficient was achieved with 4th to 6th degree ones. Logarithmic conversion of the parameters was not effective in improving the correlation. The assumption of the 3rd degree regression followed by calculation of the local minimum gave 22, 29 and 23 micrograms/100 ml Pb-B for men, women, and men + women, respectively, as the threshold Pb-B to induce ALA-U increase. Pb-B to elevate ALA-U to the 95% upper normal limit (8 mg/l, common to men and women) was 62, 50 and 58 micrograms/100 ml for men, women and men + women, respectively. The validity of the 3rd degree regression assumption as a tool to calculate a threshold from experimental or epidemiological data is discussed.