Tissue composition of major and trace elements in uremia and hypertension

Enrichment of boron element in follicular fluid and its potential effect on the immune function

The blood-follicle barrier (BFB) between the blood and follicular fluid (FF) can maintain the microenvironment balance of oocyte. Boron, an exogenous environmental trace element, has been found to possibly play an important role in oocyte maturation. This study aimed to examine the distribution characteristics of boron across the BFB and find the potential effect of boron on FF microenvironment. We analyzed the concentration of boron in paired FF and serum collected from 168 women undergoing in vitro fertilization and embryo transfer in Beijing City and Shandong Province, China. To explore the potential health impact of boron enrichment in oocyte maturation, a global proteomics analysis was conducted to tentatively correlate the protein levels with the boron enrichment. Interestingly, the results showed that the concentration of boron in FF (34.5 ng/mL) was significantly higher than that in serum (22.0 ng/mL), with a median concentration ratio of 1.52. Likewise, the concentrations of boron in FF and serum were positively correlated (r = 0.446), suggesting that boron concentration in serum can represent its concentration in follicular fluid to a large extent.. This is the first time to observe the enrichment of boron in the FF to our knowledge. It is interesting to observe a total of 13 proteins, which mainly belong to immunoglobulin class, were positively correlated with boron concentration in FF. We concluded that boron, as one environmental trace element, was enriched in FF from blood validated by two area in north china, which may be involved in an increased level of immune processes of immunoglobulins.

Accumulation of silver in the liver of three species of pinnipeds

Silver in the three species of pinnipeds [northern fur seal (Callorhinus ursinus), Steller sea lion (Eumetopias jubatus), and harbor seal (Phoca vitulina)] caught in the North Pacific Ocean were analyzed using inductively coupled plasma-mass spectrometry, in order to understand accumulation and distribution of silver in pinnipeds. In northern fur seals, relatively high concentrations of silver were observed in the liver and body hair. Some 70% of the silver burden was concentrated in the liver. Hepatic silver concentrations were significantly correlated to age in northern fur seals (r = 0.766, P < 0.001, n = 49) and Steller sea lions (r = 0.496, P < 0.01, n = 28). Levels of silver concentrations per wet weight (microgram g-1) in the three pinnipeds ranged from 0.04 to 0.55 for northern fur seals, from 0.1 to 1.04 for Steller sea lions and from 0.03 to 0.83 for harbor seals. Silver concentrations in liver for all pinnipeds were significantly correlated with mercury, and selenium (P < 0.001). Molar ratios between silver to selenium approximated 1:180 in northern fur seals, 1:120 in Steller sea lions, and 1:60 in harbor seals. The silver-mercury molar ratios were approximately 1:170 in northern fur seals, and 1:80 both in the other species. Increase in silver accumulation in the liver was caused by the retention in nuclei and mitochondria fraction together with mercury and selenium in the cells of northern fur seals.

Effects of elements on blood pressure

This article present a comprehensive review of all known elements involved in blood pressure control. Data source was by computerized literature searches. A total of 28 elements have been documented as being involved in blood pressure control. The individual elements react directly and indirectly in a variety of metabolic and structural activities known to participate in blood pressure regulation. Reports from both experimental animal and human subjects are presented. The role of certain elements in blood pressure control is controversial. Conversely, important established functions of dosage, absorption, storage, and excretion of individual elements are known and are described in relation to blood pressure control. Some elements are pressor, whereas others are depressor in action, and this article demonstrates the important role elements play in the control of blood pressure.

Silver concentrations in human tissues. their dependence on dental amalgam and other factors

Human tissue samples (liver, kidney cortex, 5 brain regions: grey matter of cerebrum, white matter of cerebrum, nucleus lentiformis, cerebellum, brain stem) from 173 decreased persons were analysed for silver (Ag) by GF-AAS (Graphite Furnace Atomic Absorption Spectrometry) and the results compared with the number of teeth with amalgam fillings and the concentration of inorganic mercury (Hg), which had been determined in the same tissue samples in a previous study. It was found that the mean Ag concentrations in liver and brain of adult females are approximately twice that of males. Moreover, the Ag concentrations, especially in the brain, depend possibly on age. To exclude these confounding factors as far as possible, the influence of dental amalgam and the correlation of Ag and Hg were evaluated only in a sub-group of 93 males, aged 11-50 years. In this sub-group statistically significant correlations were found between the number of teeth with dental amalgam and the Ag concentrations in the cerebral cortex and the liver. No such correlation was found for the kidney. Ag and inorg. Hg correlate well in this sub-group in the liver, but not in the cerebral cortex or the kidney. Individuals from this sub-group with (i) 0-2 and with (ii) more than 9 teeth with amalgam fillings show mean Ag concentrations (micrograms/kg in tissue wet weight, geom. mean) of 1.59 and 5.41 in the grey matter of cerebrum, 1.42 and 4.25 in the white matter of cerebrum, 1.53 and 4.89 in the nucleus lentiformis, 1.95 and 5.02 in the cerebellum, 1.05 and 3.27 in the brain stem, 3.40 and 8.15 in the liver and 0.42 and 0.44 in the kidney cortex. In contrast, comparing all individuals under investigation with only 0-2 teeth with amalgam no correlation between Ag and inorg. Hg could be found in liver, kidney cortex or cerebral cortex. These results show that amalgam fillings release Ag as well. Considering the different toxicokinetics of Ag and Hg it can be concluded that Ag is a reliable marker for the fact that the elevated concentrations of inorg. Hg found in tissues of individuals with amalgam fillings derive mainly from these fillings and not from other theoretically possible sources.

Selenium in uremia

The importance of selenium as an essential trace element for man has been increasingly recognized during the last several years. Selenium deficiency has been associated with cases of congestive cardiomyopathy, skeletal myopathy, anemia, enhanced cancer risk, elevated incidence of cardiovascular disease, immune system alterations, hair and nail changes, and abnormalities in thyroid hormone metabolism. These symptoms are frequently present in chronic uremic patients. Nevertheless, the prevalence and significance of selenium deficiency in the uremic syndrome is still not clearly defined. This article reviews the selenium status in chronic uremic patients, the supposed pathogenetic mechanisms of selenium disturbance in uremia, and the possible role of selenium deficiency on some uremic abnormalities.

Hemodialysis with regenerated cellulosic membranes does not reduce plasma selenium levels in chronic uremic patients

Selenium (Se) is considered an essential and very important trace element for humans. Se blood levels are frequently low in end-stage renal disease (ESRD) patients, but very little has been established concerning the mechanisms that could modify Se status in uremia, including a supposed dialysis-mediated Se depletion. In order to verify whether hemodialysis (HD) can induce a loss of Se, thereby leading or contributing to a low plasma Se concentration, we investigated the effect of HD procedure with the most commonly used regenerated cellulosic membrane (Cuprophan) on plasma Se levels in 20 uremic patients on HD for 62.5 +/- 49.4 months. Plasma Se levels were also determined in 15 chronic renal failure (CRF) nondialyzed patients and in 28 age-matched healthy controls. Se concentration was determined by atomic absorption spectrophotometry. Plasma Se levels of both HD patients (61.3 +/- 8.5 micrograms/L) and CRF nondialyzed patients (56.4 +/- 10.1 micrograms/L) were significantly lower than in normal subjects (78.3 +/- 9.7 micrograms/L, p < 0.001). In CRF nondialyzed patients, a significant (p < 0.05) negative correlation was found between the plasma Se concentration versus serum creatinine values. Within the HD group, plasma Se levels significantly increased after the HD procedure (72.8 +/- 17.2 micrograms/L, p < 0.02) together with hematocrit and total plasma protein values (p < 0.05 and p < 0.001, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Measurement of aluminium in clinical samples

Measurement of aluminium in clinical samples is important for the protection of patients with chronic renal failure, and for investigations of dementia. The types of specimen that need to be analysed include body fluids and tissues, dialysis fluids, water and foods and the concentrations that may be found can range from around 1 microgram/L to several mg/L. Although techniques must afford exceptional sensitivity they will also be susceptible to the effects of external contamination and it is imperative that those involved with the analysis, from sample collection through to the determination, ensure that precautions are taken to prevent undue addition of the metal. Of the methods that may be used ETAAS is clearly the most appropriate. Great care is required to achieve reliable performance but with experienced personnel very good results can be obtained. Regular reviews of recent analytical developments are presented in the Atomic Spectrometry Updates series and these are recommended to those who may wish to look for further information.

Effect of nickel on oxygen free radical metabolism. Inhibition of superoxide dismutase and enhancement of hydroxydopamine autoxidation

The effect of nickel on superoxide dismutase activity (SOD), as well as on rate of hydroxydopamine oxidation, was studied in vitro since lipid peroxidation has been implicated in cell damage by nickel, whose toxicity and carcinogenicity are well established. Nickel strongly inhibits SOD activity. The degree of inhibition is directly proportion to the nickel concentration (tested range 0.066 to 0.33 microgram/mL in the reaction mixture); to the substrate concentration (tested range 0.4 x 10 4M to 1.1 x 10 4M 6-hydroxydopamine); and to reaction mixture. Autoxidation of 6-hydroxydopamine was increased by nickel concentrations higher than 15 micrograms/mL. The combination of excessive oxygen free radical production and inhibition of their elimination by inhibition of SOD activity may contribute to the nickel toxicity that has been reported in industrial accidents, as well as to the high incidence of cancer occurring in nickel workers. It may also contribute to many complications in uremic patients, in whom increased serum nickel levels were reported to be in a similar range to those inhibiting SOD.

Calcium metabolism in uremic nephrocalcinosis: preventive effect of verapamil

The aim of the present study was to examine calcium metabolism of the renal cortex in experimental chronic renal failure, together with morphologic criteria of nephrocalcinosis and to determine the effect of chronic verapamil administration on these parameters. In subtotally nephrectomized (SNX) rats 3 weeks after surgery, renal cortical calcium content increased more than two-fold. 45Ca incorporation into renal cortical slices in SNX revealed a 35% increase, associated with a 50% increase in a lanthanum-resistant fraction of 45Ca uptake. Radiocalcium wash-out curves in this group demonstrated abnormal retention of the isotope for up to 30 min of incubation. In contrast, radiocalcium incorporation and wash-out in SNX rats chronically treated with verapamil were similar to that obtained in the sham group. Verapamil administration significantly reduced, but did not normalize, renal cortical calcium content. Von Kossa staining demonstrated the deposition of calcium in the renal parenchyma of SNX rats. Ultrastructurally, it was accompanied by mitochondrial disorganization and calcification, as well as by the tubular basement membrane destruction and mineralization. These morphologic patterns of nephrocalcinosis were significantly ameliorated in SNX rats treated with verapamil. We conclude that chronic verapamil administration results in amelioration of uremic nephrocalcinosis.

Trace elements in human body fluids and tissues

Published figures for trace element concentrations in body fluids and tissues of apparently healthy subjects are widely divergent. For a considerable time, the apparent disparities were readily ascribed to biological sources of variation such as age, sex, dietary habits, physiological conditions, environmental exposure, geographical circumstances, or similar influences. Growing evidence, however, suggests that this interpretation may be seriously questioned in numerous instances. First, values obtained in reference materials leave no doubt that some previous studies must have been subject to gross analytical inaccuracies. Second, it has now been thoroughly documented that inadequate sample collection and manipulation may drastically distort the intrinsic trace element content of biological matrices. This review scrutinizes data reported by a number of investigators. In an effort to settle the currently flourishing confusion, critically selected reference values are set forth for trace element levels in human blood plasma or serum, packed blood cells, urine, lung, liver, kidney, and skeletal muscle tissue.

Does cadmium contribute to human hypertension

In 1962 Schroeder reported marked hypertension in rats chronically fed a very low cadmium diet and 5 ppm cadmium in water, but subsequently he reported only moderate hypertension. Using Schroeder's food and water, but a slightly less cadmium-free environment, we repeatedly induced mild hypertension with 5 ppm cadmium, mild because control pressures were higher not because cadmium-fed animals had lower pressures. Seven laboratories have observed hypertension after feeding cadmium; six have not. Thus, chronically fed cadmium can induce hypertension in rats, but conditions are important. Additional observations on cadmium-induced hypertension indicate that: (1) concentrations from 0.1 to 5 ppm cadmium in water are pressor; (2) sex, strain, and age of animals are apparently not limiting factors; (3) there is associated sodium retention; (4) there is a concomitant decrease in the high energy phosphate content of tissues. Rats with cadmium-induced hypertension have renal cadmium concentrations which bracket those of the average environmentally exposed American or European. Finally, renal cadmium concentrations in man were significantly higher (p less than 0.05) for "hypertensives" than for normotensive "matches" in five of nine reported series, lower in one, and similar in three, with all series being small and suboptimal in subject selection.

[Chromium--its community hygienic importance]

The present contribution is a literature survey of the presentday knowledge of the chromium contamination of the biosphere. It gives an insight into the absorption mechanism, accumulation and toxicity of chromium in man, and deals with its tolerance. Preliminary investigations into the chromium distribution and burden in the territory of the GDR are presented.

Silicon nephropathy

A patient with excessive industrial exposure to silicon and an elevated silicon content in his renal tissue was found to have a distinctive nephropathy, characterized pathologically by changes in the glomeruli and proximal tubules, and manifested clinically by albuminuria and hypertension. Proximal tubular function was intact. From a biochemical standpoint, this finding correlates with the demonstration in vitro that, in contrast to cadmium, a known cause of Fanconi syndrome, silicon does not inhibit renal cortical sodium-potassium-adenosine triphosphatase (Na-K-ATPase).