In this pilot study the concentration of cadmium was determined quantitatively in samples of renal cortex of 22 kidney cancer patients and 19 controls. Data on the three main sources of exposure to cadmium-diet, cigarette smoking and occupation-were obtained through interviews. No significant difference in Cd concentration between the tumor samples and the controls could be found. The mean Cd concentration was 50.9 +/- 25 mg/kg dry weight for cancer patients and 55.2 +/- 50 mg/kg for controls. Further, it was established that the age-dependent relationship for cadmium in the cortex was not valid for smokers.
Total mercury (Hg-T) content in scalp hair of 59 pregnant and nursing women-with normal to high fish and seafood consumption-resident in fishing villages distributed throughout the coastal zone of the Eighth Region of Chile, and of 7 pregnant and nursing women-with negligible or no fish and seafood consumption-resident in a town located inland (Pinto) in the same region, was determined. Hair samples were collected, washed and stored according to IAEA recommendations, and were wet-digested in sealed Pyrex ampoules prior to the determination of Hg-T by gold amalgamation cold-vapour atomic absorption spectrometry. The absolute detection limit was estimated as 0.13 +/- 0.01 ng Hg-T (3 x sigma B1). Accuracy and precision were assessed with the aid of various biological and environmental certified and standard reference materials including human hair, and were satisfactory for ppm and sub-ppm Hg-T. Instrumental neutron activation analysis was used as a reference method for external quality control. The Hg-T content in hair of the study group (2.06 +/- 1.45(8) mg/Kg) was significantly higher than that of the control group (0.43 +/- 0.18(4) mg/kg) (p = 0.0001). These results were characterized according to geographical location, fish and seafood consumption, age and residence period in the fishing village.
In the present study, the effect of zinc deficiency on erythrocyte membrane lipids of force-fed rats that received either a diet with coconut oil and safflower oil (86:14, w/w) or a diet with fish oil and safflower oil (91:9, w/w) was investigated. Zinc deficiency caused in the rats fed both types of dietary fat an increase in the amounts of total phospholipids and individual phospholipid classes in erythrocyte membranes. In the rats fed the coconut oil diet, zinc deficiency caused an increase in the proportion of docosahexaenoic acid (22:6) in phosphatidylcholine (PC), diacyl phosphatidylethanolamine (PE), phosphatidylserine (PS), and in total erythrocyte membrane fatty acids. In contrast, in the rats fed the fish oil diet, zinc deficiency caused an increase in the proportion of docosahexaenoic acid only in PC, but not in the other phospholipids. However, in these rats, changes in the ratio between eicosapentaenoic acid (20:5) and the n-3 fatty acids with 20 and 22 carbon atoms were observed in PC, diacyl PE and plasmalogen PE. The most pronounced changes in fatty acid composition due to zinc deficiency in the rats fed both types of fat occurred in PC. There was a relationship between the changes in the composition of plasma total fatty acids and the changes in fatty acid composition of erythrocyte membrane PC caused by zinc deficiency in the rats fed both types of dietary fat. The amount of cholesterol was similar in all treatment groups. However, zinc-deficient rats fed the coconut oil diet-but not those fed the fish oil diet-had an increased ratio between total phospholipids and cholesterol. Thus, the study shows that the effect of zinc deficiency on erythrocyte membrane lipids is to some degree similar for rats fed a coconut oil diet and rats fed a fish oil diet, and to some degree different.
Adverse effects on hematopoiesis and renal function have been reported in both animals and humans exposed to high doses of lead for a protracted period of time, but little is known about the interrelationship between these two target organ systems. The present study examines rats exposed via drinking water to high dose (5000 mg/L) or low dose (100 mg/L) lead, either continuously or discontinuously, for periods ranging from 1 to 12 months. In addition to blood lead, indices of hematological abnormalities included hematocrit, zinc protoporphyrin (ZPP) and red blood cell (RBC) membrane sodium-potassium-activated adenosine triphosphatase (Na-K-ATPase). Renal function abnormalities were assessed by measurements of glomerular filtration rate (GFR) by the single injection 125-I-iothalamate technique and urinary excretion of the proximal renal tubular enzyme, ligandin. Blood lead and GFR correlated positively during the first 6 months of lead administration, reflecting a stimulatory effect of lead on renal hypertrophy and GFR during this time period. When this distorting effect was factored out, there were few residual correlations between renal and hematological abnormalities. The only significant relationship between GFR and hematological parameters of lead toxicity was a negative correlation between GFR and RBC membrane Na-K-ATPase in animals treated with high dose lead for 6 months and observed at the end of 12 months (discontinuous group).(ABSTRACT TRUNCATED AT 250 WORDS)
In a total number of 275 dogs of various ages, sex and breed, blood lead concentrations (BLC) and erythrocyte ALAD activity were measured. Sixty-six of the dogs were living in lead mining areas (Group A), 157 in urban areas (Group B) and 52 in rural areas (Group C) of Greece. Mean BLC differed significantly (P < 0.05) between locations and were 326,97 and 68 micrograms/L, respectively. Mean ALAD activity was significantly different (P < 0.05) only between Groups A and B as between groups A and C. A significant (P < 0.05) negative correlation existed between BLC and ALAD activity. A normal range of erythrocyte ALAD activity of 807-992 mumol/PBG/LRBC/h was established for dogs. None of the 33 Group A dogs and 2 of the Group B dogs that had a BLC of 350 micrograms/L presented clinical signs indicating acute or chronic lead intoxication. No erythrocyte basophilic stippling or large number of nucleated red blood cells were seen in the 30 dogs of Group A with BLC > 350 micrograms/L.
To obtain further insight into the role of selenium in the development of atherosclerosis, plasma selenium and lipid parameters were determined in 126 Portuguese subjects living in the region of Lisbon, 60 women and 66 men, 20-60 years old, divided up in to three groups according to their plasma lipid profile: Group I consisted of normolipidemic subjects having plasma triglycerides and total cholesterol < 200mg/dL; Group II was composed of hypercholesteremic subjects with total cholesterol > 200mg/dL and plasma triglycerides < 200mg/dL; Group III was composed of hypercholesteremic and hypertriglyceremic subjects having total cholesterol and plasma triglycerides > 200mg/dL. Respective values for mean plasma selenium (+/- SD) in the groups were: 93 +/- 18 micrograms/L, 90 +/- 17 micrograms/L and 96 +/- 18 micrograms/L. A weak significant difference in plasma selenium between women and men was, however, observed in Group I (87 +/- 20 micrograms/L vs. 100 +/- 11 micrograms/L, p < 0.05). Regression analysis showed no significant relationship between plasma selenium and lipid parameters, except in the most hyperlipidemic women of Group III, where a weak correlation between plasma selenium and the HDL-cholesterol/total cholesterol ratio (r = 0.80, p < 0.05) was observed. The present study suggests that the relationship between selenium and HDL-cholesterol has to be further examined, taking into account nutritional, metabolic and genetic factors.
This report is a summarization of preliminary results from a study of dietary Se intake in a seleniferous area in order to determine safe levels. All patients have symptoms of toxicity: broken hair strands or various levels of nail damage. Finger-nail signs were the first symptoms used for diagnosis of selenosis in this work. Based upon the lowest blood-Se level of five subjects with persistent overt finger-nail signs of selenosis, it was found in 1986 that the individual marginal toxic blood Se level (LOAEL) and the corresponding Se intake were 1054 micrograms/L and 910 micrograms/d, respectively. To re-examine the clinical signs and blood Se levels of the five individuals and to see how the two are correlated, a study was conducted in July 1992 at the same location in the seleniferous area. The results showed that along with the absence of clinical signs, the average blood Se level had decreased from 1346 to 968 micrograms/L. The corresponding safe Se intake per day would be 819 +/- 126 micrograms (15 micrograms/kg B.W. or approximately 800 micrograms per day, which is suggested as the mean No Adverse Effect Level (NOAEL), and the lower limit of the 95% confidence interval, 600 micrograms per day would approximately the maximum individual safe Se intake. For safety, 400 micrograms is again proposed as the Maximum Safe Daily Dietary Se Intake. Problems inherent in this estimation have been discussed.
The influence of methionine and Zn supplementation on the therapeutic efficacy of calcium disodium ethylenediamine tetraacetic acid (CaNa2 EDTA) and 2,3-dimercaptopropane 1-sulphonate (DMPS) in lead intoxication was investigated in rats. The combined treatment with CaNa2 EDTA and methionine +Zn or DMPS and methionine +Zn was more effective than the respective chelator alone in decreasing the blood and tissue burden of Pb and increasing urinary excretion of Pb, with the former combination being more effective than the later. However, simultaneous supplementation of the amino acid and essential trace element did not improve upon the efficacy of the chelator in reversing lead-induced biochemical alterations.
In this paper a flow injection manifold for the sequential determination of ionic and total calcium in a small (75 microL) sample of saliva is presented. This setup incorporates two detectors, a tubular potentiometric detector and an atomic absorption spectrophotometer, for determining the ionic and total calcium, respectively. Furthermore, the saliva samples can be injected directly into the manifold without any pre-treatment or loss of carbon dioxide. The results of the analyses of 20 saliva samples were in good agreement with those obtained by the two reference procedures, the direct potentiometry for ionic calcium and atomic absorption spectroscopy for total calcium. The paired Student's t-test showed that there were no statistical differences in the results obtained. The relative standard deviations of ten consecutive measurements of the same salive sample were approximately 3% for ionic calcium and 4% for total calcium. Effects of differences in coexisting ions, ionic strength, and pH between standard solutions and samples were negligible.
The Cu, Zn, Cr, Fe, and Ni concentrations from the atherosclerotic plaques in the abdominal aorta obtained from 40 patients who died of coronary heart disease (CHD) were measured. In 32 of them the clinical and anatomical diagnosis was ischemic heart disease (IHD) and in 8 of them it was acute myocardial infarction (AMI). Concomitant determinations of the concentrations of the above trace elements were determined in 16 normal aortas from subjects who died in accidents or from causes other than atherosclerosis (C). The determinations were done by means of a Perkin-Elmer atomic absorption spectrophotometer, Model 300. The results are expressed in mg/kg of dried tissue. The Cu, Zn, and Cr concentrations were significantly lower (p < 0.01) in the atherosclerotic plaques of abdominal aorta of the deceased patients with IHD and AMI than in the control group. Iron had the tendency to rise but not significantly. The nickel level in the atherosclerotic plaques from abdominal aorta did not change significantly as compared to the controls. We attribute the low values of copper in the atherosclerotic aortic tissue in IHD and AMI to a shift of copper from aortic tissue into the blood. At present, there is no explanation for the low concentration of zinc and chromium in atherosclerotic aortic tissue.
Early morning urines were collected on each of three days (Monday-Wednesday) from 19 male stone-formers and 20 healthy male controls. Concentrations of 10 elements were determined using inductively coupled plasma atomic emission spectroscopy, graphite furnace atomic absorption spectroscopy and particle induced x-ray emission spectrometry. Data were treated using multivariate statistical methods. The results showed that the concentrations of several elements in the control urines were significantly raised on Mondays and that controls and stone formers differed with respect to certain elements, also on Mondays. The observed elevations were termed the "weekend effect". It is suggested that while stone-formers may regulate their diets throughout the entire week, normals may indulge in dietary excesses over the weekend. The weekend effect highlights the danger of placing too much emphasis on a single measurement of a urinary parameter and alerts investigators to take cognizance of the day on which urine collections are effected, especially when attempting to identify abnormal renal excretion patterns in stone-formers by comparison of their urinary variables with those of controls.
Serum selenium levels of 160 healthy Greeks were determined by Zeeman-effect background-corrected atomic absorption spectrometry. Mean value for 101 men (70.7 +/- 16.2 micrograms/L) tended to be higher, but not statistically significant, compared to the mean value for 59 women (64.9 +/- 14.7 micrograms/L). When the subjects were divided into various age groups there appeared to be some increase as a function of age. Compared to the extensive literature data on serum Se levels for various countries healthy Greeks proved to be at the lower concentration range. The scarce, but conflicting literature data on serum Se values for Greeks is discussed.
A simple method for iodine determination in urine and water samples is presented. After digestion of the sample with chromic acid, the iodate produced was converted to iodide by the addition of a strong solution of sodium sulphite. The iodide was then precipitated as palladium iodide using a solution of palladium chloride. The precipitate was filtered through membrane filter paper, air-dried and analyzed using the Energy Dispersive X-Ray Fluorescence (EDXRF) method.
Microgram quantities of dental plaque were taken near amalgam fillings, gold crowns and intact teeth. Such extremely small samples can be analysed by total reflection X-ray fluorescence (TXRF), a fairly new variant of energy dispersive X-ray fluorescence (EDXRF). More than sixty samples were examined directly without chemical pretreatment. Fifteen elements of interest were detected simultaneously within a wide range of mass fraction and with detection limits of several mg/kg. A significant correlation of the Hg-accumulation in plaque and the amalgam fillings was established. Near these fillings Hg mass fractions can reach a level of 300 mg/kg. The results for other elements, e.g. Au, are less significant.
Selenium consumed by humans in foods and in supplements exists in a number of different organic and inorganic forms including selenomethionine, selenocysteine, selenate and selenite, Animal and human studies have established that the bioavailability of the selenium depends upon the chemical form, which also influences the distribution of selenium in the body. These studies have included urinary excretion of selenium following ingestion of different forms of selenium, and the response of tissue selenium concentrations and activities of functional selenoproteins to these selenium compounds, Selenomethionine is retained in tissue proteins to a greater extent than selenocysteine and the inorganic forms, but the selenium is not necessarily immediately available for functional selenoproteins. A number of other factors besides chemical form may also influence the bioavailability and distribution of selenium, including other dietary components, selenium status, physiological status and species. Knowledge of these factors and of speciation of selenium in foods, tissues and functional selenoproteins is important for the accurate assessment of selenium status. Speciation of selenium also has implications with respect to the determination of selenium requirements and to the investigation of relationships between selenium status and health and disease.
To obtain reference values for plasma and erythrocyte selenium concentrations blood specimens were collected from healthy adults from the Bratislava region. In 174 people, 20 to 60 years old, a plasma Se concentration of 56.2 +/- 8.5 micrograms/L and in 133 persons an erythrocyte Se level of 95.3 +/- 16.3 micrograms/kg were found (mean +/- SD). Selenium levels showed a normal distribution in plasma and erythrocytes. No differences were found according to sex or age. These results indicate that the Slovak population has a low Se status, with values for plasma Se being among the lowest in Europe.
The role of GSH concentration and GSSG reductase activity in age differences in chromate nephrotoxicity was investigated. Young and adult rats were injected with 2 and 1 mg sodium chromate/100 g body weight (BW), respectively, which led to equal Cr concentrations in renal tissue. Cr nephrotoxicity was lower in young than in adult rats. It was shown that from 30 minutes after the chromate injection GSSG reductase activity in renal tissue was increased in adult but decreased in young rats by the chromate. GSSG reductase activity was increased in young rats by pretreatment with phenobarbital. The consequence was an enhancement of chromate nephrotoxicity as shown by proteinuria. Renal GSH concentration is lower in young rats and limiting for chromate reduction in vitro in these animals. Therefore, GSH concentration was increased by pretreatment with N-acetylcysteine, which enhanced chromate nephrotoxicity significantly. These results reflect the important role of the GSH oxidoreduction system in chromate nephrotoxicity and its relationship to age differences.
In this study we determined the serum selenium concentraction of 218 healthy individuals at different ages, in Ankara, using a spectrofluorimetric method. The mean selenium levels were found to be 45 +/- 10 micrograms/L in cord blood at birth; 69 +/- 13 micrograms/L in 2 month-12 month-old infants; 77 +/- 12 micrograms/L in children aged > 12 months-16 years; and 74 +/- 16 micrograms/L in adults aged 18-48 years. Selenium concentrations showed age dependency, increasing significantly in childhood but decreasing after 40 years of age. No relation to the sex, dietary habits, socioeconomical status or hematological parameters such as hemoglobin concentration and white blood cell count, was observed. The results obtained thus suggest that the status of selenium in Ankara residents is in a range that could be considered as safe and adequate.
The concentrations of trace elements in hair were measured in 108 healthy subjects (60 males and 48 females, mean age 46-years) resident on Atafu (Tokelau) and in 83 subjects (63 males and 20 females, mean age 26-years) living on Kitava island (Papua New Guinea). On Kitava, a traditional subsistence lifestyle uninfluenced by Western dietary habits is still maintained, but on Atafu the dietary habits have been modified by the inclusion of such imported foods as rice, flour, sugar and canned meat and fish. The concentrations of zinc and magnesium in hair were significantly higher in the Kitava than in the Atafu subjects, whereas those of copper were similar in both groups, and those of selenium, mercury, lead and cadmium were higher in Atafu subjects. The levels of serum copper, magnesium and selenium concentrations in Kitava subjects were not so low as to indicate any trace element deficiency. The higher hair content of mercury, lead and cadmium found among Atafu subjects might be due to consumption of marine foods contaminated with metals, consumption of canned foods, or frequent cigarette smoking, though it is difficult to single out any specific factor.
The aim of the present investigation was to evaluate abnormal changes in trace element concentrations during carcinogenesis. First, Al, Zn and Cu in the liver tissues of rats were measured by atomic absorption analysis over a half year of hepatocarcinogenesis. Male Wistar rats were given carcinogenic food containing 600 mg/kg of 3'-methyl-4-dimethylaminoazobenzene (3'-MeDAB) in a basal diet for several months. After 4 to 6 months of feeding, hepatocarcinomas developed in the rats. Zn and Cu concentrations in the hepatocarcinomas of the 3'-MeDAB group significantly decreased as compared with normal liver tissues of the control groups. On the other hand, the aluminum concentration in the hepatocarcinomas was more than three times that in the normal liver tissues.The Al and Se contents of developed gastric and mammary cancers were measured in Experiment II. Male and female rats were given 1-methyl-3-nitrothoguanidine(MNNG) and 2,7-dimehtylbenz(a)anthracene(DMBA), respectively. After several months, carcinomas developed in over half of the rats. The Al and Se concentrations in cancers, livers and the blood were determined by atomic absorption analysis. It was shown that both gastric and mammary carcinomas contained a high level of aluminum and very little selenium in comparison with normal liver tissues. The present study demonstrated that aluminum accumulated in experimentally induced carcinomas in rats, i.e., cancers of the liver, stomach, duodenum and mammary glands.
