2009 H1N1 influenza infection in Korean healthcare personnel.

Healthcare personnel (HCP) can acquire influenza and transmit it to patients and other hospital staff. The aim of this study was to evaluate the attack rate of HCP by the 2009 H1N1 influenza virus during the 2009 pandemic influenza season in Korea. HCP infected with H1N1 virus were asked to fill out a questionnaire, which included job type, method of diagnosis, facility type, history of contact with patients infected by H1N1 virus, vaccination status, and use of personal protective equipment. A total of 328 HCP (female 68.6%, 225/328) were infected with H1N1 virus at the nine study centers. The highest attack rate was in physicians, followed by nurses and nurses' aides. Transmission occurred primarily after contact with outpatients (27.8%), followed by contact with inpatients (21.6%). Most (77.3%) of the infected HCP never used an N95 mask during contact with patients. Surgical masks were always used by 29.4% of the subjects and usually or intermittent used by 46.9%. The peak incidence of the H1N1 infection among HCP preceded that among the general population. Among HCPs, physicians, nurses, and nurses' aides were at the greatest risk of H1N1 infection. HCP should be more vigilant and protect themselves with appropriate personal protective equipment during the influenza season.

Estimates of mineral intakes using food composition tables vs measures by inductively-coupled plasma mass spectrometry: Part 1. calcium, phosphorus and iron.

OBJECTIVES: To examine the accuracy of food composition table (FCT)-based estimation of dietary nutrient element intake in reference to the instrumental measurement by inductively-coupled plasma mass spectrometry (ICP-MS). DESIGN: Cross-sectional study. SETTING: Communities. SUBJECTS: 884 adult non-smoking women in 23 study sites in 6 areas in Asia (i.e. China (Mainland), China (Taiwan), Korea, Japan, Malaysia and the Philippines. METHODS: 24-hour food duplicate samples foods offered by the women were subjected (1) to the estimation of daily dietary intake of calcium (Ca), phosphorus (P) and iron (Fe), using 6 types of national FCTs one for each area, and (2) to ICP-MS analysis for the measurement of the same elements. RESULTS: Comparison of the estimated values (E) with corresponding measured values (M) in terms of the mean (E)/(M) ratio for each area showed that the ratio was various among the 6 areas studied. Ca showed smallest deviation (69 to 165%) from the agreement (100%), which was followed by P (113 to 306%), whereas Fe showed the largest deviation (124 to 368%). CONCLUSIONS: Caution should be exercised in using FCTs for estimation of dietary Fe intake. The wide variation was not due to the use of the FCT established for each area, because the inter-study site variation within one area was as large as the inter-area variation.

Estimates of mineral intakes using food composition tables vs measures by inductively-coupled plasma mass spectrometry: Part 2: sodium, potassium, magnesium, copper, zinc.

OBJECTIVES: To examine the accuracy of food composition table (FCT)-based estimation of dietary nutrient element intake in reference to the instrumental measurement by inductively-coupled plasma mass spectrometry (ICP-MS), as an extension of the first part of this study. DESIGN: Cross-sectional study. SETTING: Communities. SUBJECTS: 782 adult non-smoking women in 21 sites in 4 areas [China (Mainland), Japan, Korea and Malaysia] in Asia. METHODS: 24-h food duplicate samples offered by the women were subjected 1. to the estimation (E) of daily element intake taking advantage of national food composition tables (FCTs) and 2. to the measurement (M) by inductively-coupled plasma mass spectrometry (ICP-MS). The two sets of the results were compared in terms of the (E)/(M) ratio. Because of the limited availability of the element database in the FCTs, the comparison on Na and K was possible in the 4 areas, whereas that of Mg, Cu and Zn was only in two areas of China (Mainland) and Japan. RESULTS: The (E)/(M) ratio was in a relatively narrow range of 75 to 114% in case of Na, and 91 to 120% for K (with one exception of 201% for K in Malaysia). Correlation coefficients between (E) and (M) were statistically significant for both Na and K in the 4 areas. In cases of Mg, Cu and Zn, agreements were generally poor, and the (E)/(M) ratio was close to 100% only in the cases of Cu and Zn in Japan. CONCLUSIONS: In overall evaluation combining the results on Ca, P and Fe in the preceding report with the results in the present report on Na, K, Mg, Cu and Zn, FCT-based estimation generally did not agree with the measure by ICP-MS. The disagreement did not allow precise FCTs-based estimation of dietary intakes of these nutrient elements, possibly except for Na.

Exposure of citizens in China and in Japan to lead and cadmium: a comparative study.

To compare the background exposure of general urban populations to lead (Pb) and cadmium (Cd) in China and Japan, 250 adult women in five Chinese cities and 72 women in three Japanese cities were surveyed by means of collection and analyses of food duplicate and blood samples. The results show that the geometric mean dietary Pb intake and Pb level in blood were significantly higher among Chinese (24.6 microg/day and 45.8 ng/ml) than their counterparts in Japan (14.6 microg/day and 32.2 ng/ml). In contrast, Cd exposures were significantly higher among Japanese women (34.1 microg/day and 1.91 ng/ml) than among Chinese women (8.8 microg/day and 0.61 ng/ml). Thus, the public health concern should be focussed on Pb exposure for Chinese population and Cd for Japanese people.

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.

Dose-dependent suppression of toluene metabolism by isopropyl alcohol and methyl ethyl ketone after experimental exposure of rats.

In order to examine possible suppression of toluene metabolism due to coexposure to other solvents, female Wistar rats were exposed for 8 h to toluene alone (at 50 or 100 ppm), or in combination with either methyl ethyl ketone (at 50, 100, 200 or 400 ppm) or isopropyl alcohol (at 50, 100, 200, 400, 800 or 1600 ppm). Urine samples were collected for 24 h after initiation of each exposure, and subjected to analysis for two toluene metabolites, hippuric acid and o-cresol, both by HPLC. The excretion of hippuric acid, a major metabolite, was not modified when the concentrations of methyl ethyl ketone or isopropyl alcohol were low, i.e. 100 ppm or below, whereas it was reduced when methyl ethyl ketone or isopropyl alcohol concentrations were twice or more times higher than that of toluene. There were no changes in any cases in excretion of o-cresol, a minor metabolite. The observation after coexposure to methyl ethyl ketone or isopropyl alcohol at low concentration is in line with the negative interaction between toluene and methyl ethyl ketone as well as between toluene and isopropyl alcohol after occupational exposures at low concentrations. Metabolic interaction may take place when the exposure intensity is high, as observed in the present study and also after experimental exposure of volunteers to toluene and m-xylene, or occupational exposure to benzene and toluene.

Background exposure of general women populations in Japan to cadmium in the environment and possible health effects.

1. The surveys were conducted in 1990s on 470 non-smoking adult women [with no specific exposure to cadmium (Cd)] in 22 sites in six regions in Japan. 2. It was found that the dietary Cd intake (as a grand geometric mean) was 25.9 microg/day, the Cd level in blood was 2.1 microg/l, and Cd level in urine was 2.1 microg/g creat. 3. Cd in rice contributed about 30% of total dietary Cd intake. 4. There was a substantial reduction in Cd burden when compared with observation in 1980s. 5. Effects on kidney functions were essentially negative when evaluated in terms of beta2-microglobulin (beta2-MG), but might be positive when alpha1-microglobulin (alpha1-MG) was evaluated; further studies are apparently necessary. 6. No effects on liver functions were detected.

Evaluation of urinary cadmium and lead as markers of background exposure of middle-aged women in Korea: dietary intake as an influential factor.

The study was conducted to examine the validity of urinary cadmium (Cd) and lead (Pb) in comparison with the metals in blood as a biological marker of non-occupational exposure of general populations. Participants in four survey sites in Korea (107 non-smoking Korean women aged 30-49 years) offered peripheral blood, morning spot urine, and 24-h total food duplicate samples. Analysis of Cd and Pb was accomplished by graphite furnace atomic absorption spectrophotometry. The analyse levels were evaluated on an individual basis (n = 107) and also on a survey site basis, i.e. in terms of geometric means for the groups in the survey sites (n = 4). Cd in urine (as observed, or after correction for creatinine concentration or a specific gravity) correlated with Cd in blood on an individual as well as survey site basis, and tended to correlate with Cd in food duplicates on the survey site basis. Correlation of Pb in urine with Pb in blood was weaker than that of Cd in urine with Cd in blood both on the individual and survey site basis. Pb in urine correlated with Pb in food duplicates either weakly or even negatively when examined on a survey site basis. It was concluded that Cd in urine can be most probably employed as a biological marker of environmental Cd exposure of general population, whereas less support was obtained for Pb in urine as an exposure marker.

A comparison of the food composition table-based estimates of dietary element intake with the values obtained by inductively coupled plasma atomic emission spectrometry: an experience in a Japanese population.

In order to make quantitative comparison between food composition table-based estimates and instrumental measures by inductively coupled plasma atomic emission spectrometry (ICP-AES), total food duplicates were collected from 232 adult women in 10 study regions in 9 Prefectures in Japan. Daily dietary intake of 5 elements, sodium (Na), potassium (K), phosphorus (P), calcium (Ca) and iron (Fe), were estimated from the weights of food items in each duplicate by use of food composition tables. Parallel to this the intakes were measured by wet-ashing of food duplicate homogenates followed by ICP-AES analysis. Because the emission intensity of K was significantly modified by Na co-present at various concentrations, K was measured after Na concentration was reduced to the value 150 mg/L by dilution. The comparison of the two sets of the results, the estimated values and the measured values, showed that the estimated values were significantly larger than the measured values in the cases of Na, K, Ca and P (the ratio of the estimated to the measured values: 118% for Na, 115% for K, 109% for Ca; and 130% for Fe), whereas the two values essentially agreed with each other in the case of P (ratio: 93%). The differences were too large for any nutritional evaluation to be made when the method of Bland and Altman is applied. The significance of the differences in relation to nutritional evaluation of element intake is discussed.

Insufficient calcium and iron intakes among general female population in Japan, with special reference to inter-regional differences.

Dietary intakes of calcium (Ca) and iron (Fe) were investigated in 227 women (mostly housewives) in 12 regions in Japan in 1991-1993 by the 24-hour food duplicate method. Nine regions out of 12 had been previously studied in 1977-1982. Utilizing Standard Food Composition database, mean Ca and Fe-intakes in 1991-1993 were estimated to be 602 and 10.4 mg/day, respectively; the former was barely sufficient and the latter was below sufficiency when compared with the Recommended Daily Allowance in Japan for pre-menopausal women. Ca- and Fe-intake did not increase in the 10-year period. Further analysis after classification of the women into three groups of farmers in Okinawa, farmers in Mainland Japan and urban residents showed that Ca and Fe insufficiency was most evident among Okinawa farmers. The leading Ca sources were milk, pulse, vegetables and fish-shellfish, but consumption of milk was generally low, especially among Okinawa farmers. Pulse, vegetables and fish-shellfish were 3 major Fe sources; Okinawa farmers depended more on vegetables and less on fish-shellfish.

Motor neuron disease on the Kii Peninsula of Japan: excess manganese intake from food coupled with low magnesium in drinking water as a risk factor.

To identify important risk factors of motor neuron disease (MND) in a focus (Hohara) on the Kii peninsula of Japan, 24-h dietary duplicates, rice, drinking water, and soils were analysed for metals in Hohara and control areas. The manganese content in 24-h food in Hohara was significantly (P < 0.01) higher than that in the remote control areas. The incidence of MND in Hohara was well explained by the two parameters, manganese content in food and the magnesium concentration in drinking water (r2 = 0.99), suggesting that MND in this focus can be understood as a result of excess intake of manganese from food coupled with low intake of magnesium from drinking water. The reference to epidemiology and occupational medicine supports this conclusion. The crude annual MND incidence per 10(5) population in other foci may be predicted as MND = e alpha ln[beta(Mn in food)gamma/(Mg in water)], where alpha is 5.389-5.748, beta is 0.170-0.166, and gamma is 1.239-1.226.

Determination of lead and cadmium in food and blood by inductively coupled plasma mass spectrometry: a comparison with graphite furnace atomic absorption spectrometry.

To compare inductively coupled plasma mass spectrometry (ICP-MS) and graphite furnace atomic absorption spectometry (GF-AAS) as the method for determining lead and cadmium in the human diet and blood, 418 diet homogenate samples and the same number of blood samples were collected from Chinese and Japanese women and were analyzed by the two methods. The results showed that our ICP-MS method is precise and accurate, being comparable to the GF-AAS method established previously. The ICP-MS method is simple and fast spending only one-tenth of the time necessary for GF-AAS and allows simultaneous analyses of lead and cadmium with low detection limits. When applied to actual sample analysis, however, ICP-MS results tend to be 10-20% lower than GF-AAS results in the analysis of lead in the diet and blood and cadmium in blood. This is possibly due to some interference in ICP-MS and matrix of samples. As the ICP-MS results could be mathematically corrected to be equivalent to the GF-AAS results, we conclude that this ICP-MS method can be used as a routine analytical method for the determination of lead and cadmium in human diet and blood samples.

Cadmium contents in rice samples from various areas in the world.

Rice samples consumed by local populations were collected in 17 areas in the world, mostly from Asia, i.e. ten areas, but eight areas outside of Asia were also included during the period of 1990 to 1995. The samples amounted to 1546 in total, and were analyzed for cadmium (Cd) by electrothermal atomic absorption spectrometry. The data show that the highest and the lowest geometric means of Cd contents in rice from Asia was 55.70 and 2.67 ng/g, respectively, and 133.20 and 0.88 ng/g outside of Asia. The geometric mean Cd contents in rice from Japan was 55.70 ng/g, which is essentially similar to the levels determined in the early 1980s. We conclude that a substantial difference exists in Cd contents in rice for local consumption depending on the areas in the world, and that there is no significant changes in Cd levels in rice harvested in Japan over the past 10 years.

Lead content of rice collected from various areas in the world.

Rice samples consumed by local populations were collected between 1990 and 1995 in 17 areas in the world, mostly from Asia (10 areas), but also from 7 areas outside of Asia. In total, 1528 samples were obtained (about one half from Japan) and were analyzed for lead (Pb) by electrothermal atomic absorption spectrometry. When the Pb contents in rice samples were classified into 10 areas in Asia, the highest and the lowest geometric means (GMs) were for Indonesia (38 ng/g) and Australia (2 ng/g), respectively. Among 7 regions outside Asia, the GM was highest for Spain (58 ng/g) and the lowest for the USA. (3 ng/g). Moreover, inter-regional differences were significant, when more than 100 samples from one area were divided into 3-9 regions and GMs for regions were compared. There was a marked difference in Pb contents in rice by areas and regions in the world. Nevertheless, comparison by area of the present results with those reported in literature show that there has been no substantial reduction in Pb in rice in the past decade either in Japan or elsewhere in the world.

Urban population exposure to lead and cadmium in east and south-east Asia.

Information is still scarce for many Asian countries on general population exposure to two potentially toxic heavy metals of lead (Pb) and cadmium (Cd). The present review on publications from this study group is intended to provide an overview of the non-occupational exposure to Pb and Cd among general populations in east and south-east Asia. During the period of 1991-1998, surveys were conducted in four cities in south-east Asia, five cities in mainland China, and two cities each in Japan and Korea. Peripheral blood, morning spot urine and 24-h food duplicate samples were collected from 20-50 non-smoking adult women in each survey site. The samples were digested by heating in the presence of mineral acids, and then analyzed by inductively-coupled plasma mass spectrometry for the metals in blood (Pb-B and Cd-B), in urine (Pb-U and Cd-U), and in food duplicate (Pb-F and Cd-F). Measures were subjected to statistical analysis with an assumption of log-normal distribution. Pb-B, Pb-U and Pb-F levels varied substantially among the 11 urban sites; GM distributed in ranges of 32-65 microg/l for Pb-B, 2.1-7.5 microg/g cr (creatinine) for Pb-U, and 7-32 microg/day for Pb-F. The same was also the case for Cd exposure parameters, the distribution ranges being 0.5-1.8 microg/l for Cd-B, 1.2-3.1 microg/g cr for Cd-U, and 5-32 microg/day for Cd-F. It appeared that the exposure to Pb and Cd was highest in Kuala Lumpur, and Tokyo + Kyoto, respectively, and lowest in Tokyo + Kyoto and in Manila. Additional surveys in Japan showed that Pb exposure was even lower in rural areas than in Tokyo + Kyoto. When compared with the values reported in the literature, Pb exposure levels among Asian populations appear to be similar to the levels in Europe and in the United States, whereas Cd exposure seems to be higher in Asia than in Europe. The contribution of the dietary route in Pb absorption was variable and was inversely related to the extent of air pollution, whereas Cd uptake was almost exclusively via the dietary route with little contribution of the respiratory route.

Correlation between concentration in urine and in blood of cadmium and lead among women in Asia.

The objectives of the present study are to examine if there exists a quantitative relationship between lead in urine (Pb-U) and that in blood (Pb-B), and also between cadmium in urine (Cd-U) and that in blood (Cd-B) among the general populations who are environmentally (and not occupationally) exposed to these elements at various levels. For this purpose, peripheral blood and morning spot urine samples were collected in 1991-1998 from approximately 50 non-smoking adult women each in four cities in south-east 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, Cd-B, Pb-U and Cd-U. Measured values were subjected to analysis to detect possible correlation between the pairs of parameters. A significant correlation between Pb-B and Pb-U was observed when the intensity of Pb exposure (as expressed by Pb-B) was relatively high so that the correlation was significant in all cases studied when Pb-B level was, e.g. 50 microg/l or above. It was also observed that the correlation between Cd-B and Cd-U was significant when Cd-B was, e.g. > 1 microg/l. Thus, it is possible to deduce that, in environmental health, Pb-B and Cd-U levels can be estimated on a group basis from Pb-U and Cd-B, respectively, when Pb and Cd exposure levels are relatively high, e.g. with Pb-B and Cd-B of > 50 microg/l and > 1 microg/l.

Contents of pollutant and nutrient elements in rice and wheat grown on the neighboring fields.

Because of recent agricultural policy to suppress rice production, a rather rare situation occurred in one prefecture in Japan that rice and winter wheat were grown in fields neighboring each other, rice being grown from May to October, and wheat from November to June of the next year. Grains of such rice and wheat were analyzed for cadmium (Cd) and lead (Pb) by atomic absorption spectrometry, and eight nutrient minerals by inductively coupled plasma emission spectrometry. Concentrations of nutrient minerals were higher in wheat grains than in unpolished rice grains (without husk), and similar trends were observed also for Cd and Pb. Flour obtained by milling of the wheat grains had significantly less Cd and nutrient minerals than the mother grains, and such reduction was also observed by treatment of unpolished rice to polished grain. Pb concentration was also reduced by the polishing of rice. Pb in wheat flour appeared to be higher than that in whole grain. Comparisons between the final edible forms of the two cereals showed that K and Cu were higher in polished rice than in wheat flour and that such may also be the case for Cd, whereas the reverse was the case for Ca and Fe, and possibly for Pb.

Absence of mutagenicity in peripheral lymphocytes of workers occupationally exposed to methyl methacrylate.

Chromosome aberration rates and sister chromatid exchange frequency were examined in the peripheral lymphocytes of 38 male workers who were engaged in organic glass production and exposed to methyl methacrylate (MMA) vapors at the concentrations of 0.9 ppm to 71.9 ppm. The results were compared with the findings in the concurrent nonexposed male subjects. Comparison of the exposed group with the nonexposed controls showed that there were no exposure-related changes in chromosome aberration rate. SCE frequency was higher in the exposed group than in the controls, but this was considered to be due to higher ages of the former group than that of the latter. In fact, selection of nonsmokers and further classification of the exposed nonsmokers into two groups of those with exposure below and above a median MMA concentration (ca. 4 ppm) failed to show any difference among the three nonsmoking groups in cytogenetic parameters, or any dose-dependency. The present results, although in a limited number of subjects, indicate that occupational methyl methacrylate exposure under the conditions studied is not associated with mutagenicity. This conclusion confirms the absence of mutagenicity of methyl methacrylate in humans, and is in general agreement with a majority of the results of studies on mutagenicity in vitro, animal carcinogenicity and occupational cancer epidemiology of methyl methacrylate.

One-year follow-up of laser trabeculoplasty using Q-switched frequency-doubled Nd:YAG laser of 523 nm wavelength.

BACKGROUND AND OBJECTIVE: To investigate clinical efficacy and safety of a new laser treatment of open angle glaucoma that targets pigmented cells in the trabecular meshwork for disruption. MATERIALS AND METHODS: The 16 eyes of chronic open angle glaucoma patients were treated in the method similar to argon laser trabeculoplasty using Q-switched, frequency-doubled Nd:YAG laser (523 nm). The treatment results were followed and analyzed for a one-year period. RESULTS: Mean intraocular pressure reduction of 3.81 mm Hg (15%) at 3 months, 3.94 mm Hg (16.1%) at 6 months, and 4.93 mm Hg (20.2%) at 12 months from the baseline were obtained. Slightly greater reductions were seen in the responder group that consisted of eyes showing 3 mm Hg or greater reduction. Adverse reactions were minimal and not significant. CONCLUSION: This new laser trabeculoplasty has shown reasonable efficacy and safety on a limited number of eyes over a one year duration.

Antimicrobial resistance in Campylobacter spp. isolated from Ontario sheep flocks and associations between antimicrobial use and antimicrobial resistance.

The objectives of this study were to determine the prevalence of antimicrobial resistance (AMR) in faecal Campylobacter spp. from lambs and adult sheep and associations between antimicrobial use (AMU) and AMR. A total of 275 faecal samples collected during initial and final visits from 51 sheep flocks, including one feedlot, across southern Ontario were tested for the presence of Campylobacter spp. Campylobacter jejuni was detected in 52% (143/275) of the faecal samples, Campylobacter coli in 7% (19/275), Campylobacter lari in 1% (2/275) and 2% (4/275) were non-speciated Campylobacter. Broth microdilution was used to test antimicrobial susceptibility of 162 isolates to nine antimicrobials. Campylobacter jejuni isolates (n = 142) were resistant to tetracycline (39%), ciprofloxacin (4%), nalidixic acid (4%) and telithromycin (1%). C. coli isolates (n = 19) were resistant to tetracycline (74%), and azithromycin, clindamycin, erythromycin, and telithromycin (5%). The C. lari isolate displayed resistance to nalidixic acid. No statistically significant associations were found between AMU and AMR during multivariate modelling in this study.