Journal of trace elements and electrolytes in health and disease最新文献

The aim of the study was to examine the effects of oral zinc supplementation on liver ornithine transcarbamylase activity (OTC), a key enzyme in the urea cycle, in cirrhotic rats. OTC was studied in two groups of rats treated with carbon tetrachloride (CCl4): the first received zinc in the drinking water during the induction of cirrhosis; the second was the control group. Cirrhotic rats which received zinc supplementation showed an increase in liver OTC activity, positively correlated with serum and hepatic zinc content. The results suggest that zinc dietary supplementation may modify hepatic OTC activity and, therefore, plasma ammonia levels in cirrhotic rats.

In order to assess the Se status in individuals living in the Veneto region, a series of related measurements was performed. These included plasma selenium by PIXE and glutathione-peroxidase (GSH-Px) activities in plasma, red blood cells and platelets. Individuals were either normals or people suffering from various liver diseases. Moreover, an oral supplement of sodium selenite was given to 13 patients suffering from stable chronic renal failure (CRF) in parallel to 26 normals: data on plasma GSH-Px and on serum creatinine and creatinine clearance were collected either before or after supplementation. Results were in support of a relatively low selenium status: mean +/- SD plasma Se values of normals (0.82 +/- 0.17mumol/L, n = 82) were comparable to data observed in European regions where Se deficiency was already known. Even lower values were observed in those with liver diseases. Among enzyme activities, the distribution of the data of platelet GSH-Px was in further support of low Se status in the evaluated individuals. After Se supplementation, both normals and CRF patients showed a significant increase in the creatinine clearance, reflecting an improvement of the glomerular filtration rate. We suggest that more extensive surveys of the Se status should be carried out in Italy; moreover, Se supplementation may be advisable in individuals affected with moderate impairment of renal function.

We have studied the effects of lead, cadmium and hexavalent chromium in cultured human lymphocytes. Both the proliferative response and the generation of antibodies were evaluated, and the metal accumulation in the cells was measured. Lead added in the range of human exposure caused a significant enhancement in Ig production, which was related to the Pb concentration in the cells. An inhibitory effect on blastogenesis, was detected at Cd doses found in occupationally exposed subjects. Chromium induced reductions in both blastogenesis and Ig production in relation to its capability to enter the cells.

Serum Cu (S-Cu) and Zn (S-Zn) levels were determined in 1468 out of 1856 male subjects aged 55-75 years living in the Rome area who participated, between 1989 and 1990, in the second examination in an epidemiological (New Risk Factors) survey. Mean S-Cu and S-Zn concentrations were 15.98 mumol/l (mean +/- 2SD: 10.38-21.58 +/- mumol/l) and 13.69 mumol/l (mean +/- 2SD: 8.94-18.44 mumol/l), respectively. S-Cu levels were directly related to serum calcium levels (S-Ca), serum magnesium levels (S-Mg), daily cigarette consumption, total cholesterol and age (years). S-Zn levels were directly related to S-Ca, S-Mg and cholesterol and inversely related to age. A weak inverse linear relationship existed between S-Zn and S-Cu. After adjustment for body mass index (BMI), smoking habit, alcohol consumption and blood biochemistry in a multiple linear regression model, the relationship of S-Cu (direct) and S-Zn (inverse) to age remained statistically significant.

Plasma levels of TSH, T4, T3, and reversal T3 (rT3) were measured in 51 children with trisomy of the chromosome 21 and in 15 controls. Levels of TSH were higher in children with DS than in controls and rT3 levels were decreased. However, T3 and T4 levels were in the normal range. Plasmic zinc and thymulin, a zinc-dependent thymic hormone, were also decreased. After dietary supplementation with ZnSO4, levels of plasmic zinc, thymulin, TSH and rT3 were restored. A follow up of DS children one year after the cessation of zinc therapy showed that plasma levels of zinc decreased and TSH lightly increased. Zinc deficiency may play a crucial role in the pathogenesis of thyroid gland disfunction which leads to the autoimmune hypothyroidism often observed in this syndrome.

Urine samples from dogs were analyzed for 15 important elements (Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, V, and Zn) by using wet-ashing and simultaneous DCP atomic emission spectrometry. As K, Na and P influence the spectral emission of elements to be determined, matrix-matching was applied to ensure accurate metal determinations. The method was checked by analyzing standard reference materials of urine. The values found were generally in agreement (accuracy within 100 +/- 10%) with the certified values. Short- and long-term stabilities of the instrument for the elements determined ranged from 0.4 to 2.2% and from 1.2 to 6.9%, respectively. Simultaneous multi-element determination gives increased information on trace- and minor elements in urine. In the present study DCP atomic emission spectrometry is successfully applied for this purpose.

The effects of short-term starvation on serum and tissue levels of zinc, metallothionein (MT), and the activity of alkaline phosphatase (EC 3.1.3.1, ALP) were investigated with 6-month-old rats. The rats were fed a diet with adequate zinc (92mg/kg of Zn, 1.12% phytic acid) before they were starved for 0h (control), 12h, 24h, and 36h and then killed by decapitation. Fasting was accompanied by typical changes in serum parameters such as reduced glucose and protein concentrations, elevated ketogenesis, and a rapid breakdown of liver glycogen. Fasting did not alter serum zinc levels, but it did lead to a significant elevation in the percent of unsaturated serum-zinc binding capacity. Liver concentrations of zinc and MT, based both on fresh and dry weight, were increased throughout starvation. However, total liver zinc was reduced by up to 23% in response to fasting and total liver MT was slightly elevated. The increased concentrations of liver zinc and MT are, therefore, mainly a consequence of reduced liver weight. A part of the liver zinc, however, was bound to newly synthesized MT to prevent greater zinc loss. Starvation evoked no altered mucosa MT levels. Changes in kidney zinc and kidney medulla MT caused by starvation were small and not significant. In contrast to this observation some variation of kidney cortex MT was apparent. Starvation produced a permanent reduction of the serum and intestinal activity of ALP. In the liver and the medulla of the kidneys no significant differences of ALP activity could be observed. However, kidney cortex ALP was induced after 36h of fasting.(ABSTRACT TRUNCATED AT 250 WORDS)

Atomic absorption spectrometry is used to determine copper and zinc content of several duplicate meals consumed by different population groups in the Antwerp region (Belgium). Daily elemental intake, beverages not included, is calculated and proven to be below the recommended daily allowances (National Academy of Sciences, USA), except for copper intake by macrobiotics. Values obtained in this study are compared with scarce data on intake by similar groups in other countries.

The activity of catalase and glutathione peroxidase (GSH-Px) in erythrocytes and concentration of selenium in plasma and mercury in whole blood, plasma, and urine were analyzed in 36 individuals occupationally exposed to mercury vapor, in 14 individuals with skin hypersensitivity to inorganic mercury, and in 17 individuals with subjective symptoms alleged to result from dental amalgam fillings. The control group consisted of 39 individuals with amalgam fillings, but no occupational exposure to mercury. Selenium in plasma was determined by GFAAS with Zeeman background correction. After exclusion of individuals with reported intake of selenium supplement the median plasma selenium concentration in the group with occupational exposure to mercury was 1.24 mumol/L, in the allergy group 1.22 mumol/L, in the amalgam group 1.25 mumol/L, and in the control group 1.22 mumol/L. The activities of catalase and GSH-Px were similar in all groups. However, in females lower GSH-Px activity was found in the amalgam group compared with females in the control group. GSH-Px activity in smokers was slightly lower than in non-smokers. No correlations were found between concentration of selenium or mercury in plasma and activity of glutathione peroxidase or catalase in erythrocytes.

The effect of an increased intake of wheat selenium (Se) on platelet Se, serum Se, whole-blood Se, and glutathione peroxidase (GSH-Px) levels was investigated in 14 healthy Norwegian females (age 21-53 years). The intake of 60 micrograms Se per day as wheat Se, for six weeks, significantly increased the platelet Se (mean +/- SEM) from 9.1 +/- 1.1 mumol/L to 11.4 +/- 0.9 mumol/L, the serum Se from 1.43 +/- 0.18 mumol/L to 1.63 +/- 0.25 mumol/L, and the whole blood Se from 1.77 +/- 0.18 mumol/L to 2.01 +/- 0.18 mumol/L. The increase in percent of initial Se values was twice as high for platelets as for serum and whole blood. The GSH-Px levels were not altered during the experiment. Platelet Se was not significantly correlated to the Se intake initially. At the end of the experimental period, the Se in platelets reflected the total Se intake, but not with a simple linear correlation. No significant correlation between the total Se intake and the Se concentration in whole blood or serum was found.