Silicon, an important exposure marker in vivo in silicosis research.

PURPOSE: The degree of silicosis exposure is closely related to the progress of silicosis. At present, we use animal and human studies to explore whether silicon can be an important exposure marker in the development of silicosis. METHODS: Rats were randomly divided into 2 groups: (1) controls; and (2) silicosis. Rats in the silicosis group were killed at 4, 8, 12, 16, 24 h, 3, 7, 14, 21, and 28 days. Hematoxylin-eosin (HE) and immunohistochemistry (IHC) were performed to observe the histomorphology of lung tissue. The expression levels of CC16 and SP-D were detected using ELISA kits. In addition, we conducted a population study. Workers who have been selected to work in an iron mine for more than 1 year as research objects. The population was divided into four groups: silicosis exposure group (workers exposed to silica dust for more than 1 year in an iron mine were selected); patients group (silicosis patients); observation group (evidence of disease not meeting formal diagnostic criteria) and control group. Both the levels of trace silicon in the urine and blood of rats and human subjects were measured with ICP-MS. RESULTS: Serum levels of silicon were immediately increased in rats exposed to silicon dust. Similarly, our population study revealed that the silicon level in the silica exposure group and the observing group (exposed but no obvious symptoms) were significantly increased over that of the control group (P < 0.05). In subjects with extended exposure to silica, the serum and urine silicon level in exposed workers appeared to rapidly increase, reaching its peak in 1-5 years, followed by a gradual decline thereafter. Workers exposed to dust for less than 10 years were divided into subgroups by 2-year limit. The levels of serum silicon, urine silicon, TGF-ß1, and TNF-α were significantly higher than that of control group. CONCLUSION: Changes of the serum levels of silicon occurred earlier than the expression of cytokines such as TNF-α, TGF-ß1, CC16, and SP-D. The level of silicon in workers rapidly increased after exposure to silica, and the change occurred before the expression of TGF-ß1 and TNF-α. As a whole, the findings suggest that determining the level of silicon in vivo might be an effective exposure marker in the diagnosis and pathogenesis of silicosis.

Levels of Silicon in Maternal, Cord, and Newborn Serum and Their Relation With Those of Zinc and Copper.

BACKGROUND: Evidence of silicon's importance to health has been gradually accumulating. Nevertheless, there are few studies comparing serum silicon levels in newborns with maternal levels. Likewise, little is known concerning the inter-relation between silicon and other trace elements. OBJECTIVE: The present study evaluated maternal and newborn levels of serum silicon and their relation to those of zinc and copper. METHODS: We measured serum silicon, copper, and zinc in 66 pregnant women, in the umbilical cord of their infants, and in 44 newborns, by atomic absorption spectrophotometry. All the samples were from fasted subjects. RESULTS: Serum silicon level in term newborns (20.6 ±â€Š13.2 µmol/L) was significantly higher than in umbilical cord (8.9 ±â€Š3.5 µmol/L; P < 0.0001). Mean serum silicon level in maternal vein (7.7 ±â€Š3.4 µmol/L) was lower than that in umbilical cord, although differences were not significant. We also found higher levels of zinc (P = 0.008) and lower levels of copper (P < 0.0001) in cord blood compared with maternal blood. Umbilical venous/maternal venous level ratios of zinc, copper, and silicon were 1.5 ±â€Š0.5, 0.2 ±â€Š0.1, and 1.3 ±â€Š0.7, respectively. There was a positive correlation between silicon and zinc levels (r = 0.32), and a negative correlation between copper and zinc levels (r = -0.35). CONCLUSIONS: It seems that there is a positive gradient of silicon from the mother to her fetus. Silicon levels were higher in newborn than in cord blood, and correlated significantly with that of zinc but not copper. Additional investigations are needed to further define the role of silicon and its interaction with other trace elements during the perinatal period.

Positive association between serum silicon levels and bone mineral density in female rats following oral silicon supplementation with monomethylsilanetriol.

UNLABELLED: Observational (epidemiological) studies suggest the positive association between dietary silicon intake and bone mineral density may be mediated by circulating estradiol level. Here, we report the results of a silicon supplementation study in rats that strongly support these observations and suggest an interaction between silicon and estradiol. INTRODUCTION: Epidemiological studies report strong positive associations between dietary silicon (Si) intake and bone mineral density (BMD) in premenopausal women and indicate that the association may be mediated by estradiol. We have tested this possibility in a mixed-gender rodent intervention study. METHODS: Tissue samples were obtained from three groups of 20-week-old Sprague Dawley rats (five males and five females per group) that had been supplemented ad libitum for 90 days in their drinking water with (i) <0.1 mg Si/L (vehicle control), (ii) 115 mg Si/L (moderate dose) or (iii) 575 mg Si/L (high dose). All rats received conventional laboratory feed, whilst supplemental Si was in the form of monomethylsilanetriol, increasing dietary Si intakes by 18 and 99 %, for the moderate- and high-dose groups, respectively. RESULTS: Fasting serum and tissue Si concentrations were increased with Si supplementation (p < 0.05), regardless of gender. However, only for female rats was there (i) a trend for a dose-responsive increase in serum osteocalcin concentration with Si intervention and (ii) strong significant associations between serum Si concentrations and measures of bone quality (p < 0.01). Correlations were weaker or insignificant for tibia Si levels and absent for other serum or tibia elemental concentrations and bone quality measures. CONCLUSIONS: Our findings support the epidemiological observations that dietary Si positively impacts BMD in younger females, and this may be due to a Si-estradiol interaction. Moreover, these data suggest that the Si effect is mediated systemically, rather than through its incorporation into bone.

Dietary Silicon Deficiency Does Not Exacerbate Diet-Induced Fatty Lesions in Female ApoE Knockout Mice.

BACKGROUND: Dietary silicon has been positively linked with vascular health and protection against atherosclerotic plaque formation, but the mechanism of action is unclear. OBJECTIVES: We investigated the effect of dietary silicon on 1) serum and aorta silicon concentrations, 2) the development of aortic lesions and serum lipid concentrations, and 3) the structural and biomechanic properties of the aorta. METHODS: Two studies, of the same design, were conducted to address the above objectives. Female mice, lacking the apolipoprotein E (apoE) gene, and therefore susceptible to atherosclerosis, were separated into 3 groups of 10-15 mice, each exposed to a high-fat diet (21% wt milk fat and 1.5% wt cholesterol) but with differing concentrations of dietary silicon, namely: silicon-deprived (-Si; <3-µg silicon/g feed), silicon-replete in feed (+Si-feed; 100-µg silicon/g feed), and silicon-replete in drinking water (+Si-water; 115-µg silicon/mL) for 15-19 wk. Silicon supplementation was in the form of sodium metasilicate (feed) or monomethylsilanetriol (drinking water). RESULTS: The serum silicon concentration in the -Si group was significantly lower than in the +Si-feed (by up to 78%; P < 0.003) and the +Si-water (by up to 84%; P < 0.006) groups. The aorta silicon concentration was also lower in the -Si group than in the +Si-feed group (by 65%; P = 0.025), but not compared with the +Si-water group. There were no differences in serum and aorta silicon concentrations between the silicon-replete groups. Body weights, tissue wet weights at necropsy, and structural, biomechanic, and morphologic properties of the aorta were not affected by dietary silicon; nor were the development of fatty lesions and serum lipid concentrations. CONCLUSIONS: These findings suggest that dietary silicon has no effect on atherosclerosis development and vascular health in the apoE mouse model of diet-induced atherosclerosis, contrary to the reported findings in the cholesterol-fed rabbit model.

Serum silicon concentrations in pregnant women and newborn babies.

Earlier studies in animals have suggested an essential role for Si in connective tissues, but such works have not been replicated per se. Nonetheless, a study conducted in 2000 has reported that Si may be essential during pregnancy for the growing fetus, since serum Si concentrations in infants were approximately 300 % higher than those in older children and adults and serum Si concentrations in pregnant women were approximately 300 % lower than those in age-matched non-pregnant controls. To reproduce these potentially important findings, in the present study, serum Si concentrations were measured in fourteen pregnant women (15-24 weeks of gestation) and compared with those of seventeen non-pregnant, non-lactating female controls. Serum Si concentrations were also measured in fourteen full-term mothers at the time of delivery and in the umbilical cord (UC) vein and artery where possible. Fasting serum Si concentrations in pregnant women were not significantly different from those of the female controls and showed little change with advancing gestation (r 0·2). Mean serum Si concentrations in the UC vein samples were 52 % higher, while those in the UC artery samples were 235 % higher than those in the maternal forearm vein samples, although data were widely spread and differences were not significant. Mean maternal forearm vein Si concentrations at delivery were 50 % lower than those of pregnant women and female controls, but, again, these were not significant. Overall, we note that there are significant analytical challenges in comparing baseline Si levels between different groups; notwithstanding, our findings cannot confirm a reduction in fasting serum Si levels during pregnancy, but, equally, we cannot rule out higher serum Si levels in newborns than in their mothers, and further work is required.

Silicon absorption and excretion is independent of age and sex in adults.

Host factors influencing the absorption and excretion of Si are poorly understood, although previous murine and human studies have suggested that age, sex and oestrogen status may affect Si metabolism and thus function. Here, serum and urine samples were collected from twenty-six healthy adults at baseline and over a 6 h period following ingestion of 17·4mg Si (orthosilicic acid) and analysed by inductively coupled plasma optical emission spectrometry. Fasting baseline serum and urinary Si concentrations were marginally higher in older adults (51-66 years old) compared with young adults (20-47 years old); however, there was no difference in the absorption of Si into serum (overall profile, rate of Si appearance, peak concentration and time to peak) between the different adult groups. The rate of elimination of Si from serum did not significantly differ with age or sex, although serum concentration at 6 h was higher in older adults and significantly correlated with age (r 0·5; P=0·01). There were, however, no significant differences in the excretion of Si into urine (a proxy for overall uptake) between the groups, averaging approximately 45 %. Oestradiol levels did not correlate with any of the above measures of Si. Thus, overall, host age and sex did not appear to markedly influence Si absorption or excretion in human adults and no correlations were found with serum oestradiol status. The marginally higher baseline and 6 h post-dose Si levels in older adults may reflect modestly impaired renal function and/or the loss of Si from connective tissues with ageing.

[Influence of dust load on oxidant activity and antioxidant defense parameters of workers in steel factories].

The article covers data on levels of oxidative and antioxidant processes under influence of low fibrogenous dust in workers at steel mills. Reliable differences were seen between groups of workers with different dust load, dust particles size in blood, acitvity level of lipid peroxidation products occurrence--that worsens inflammatory reaction and dysfunction of lower respiratory tract. Findings are that occupations--preparation of steelpouring mixtures, converter melters, batchers--with highest silicon content of blood, if compared to other occupations and to the reference group (1.6 and 2.9 times respectively), demonstrated more intense change in parameters of oxidation processes activation (increased level of lipid hydroperoxide and malonic dialdehyde) with depressed antioxidant defense (lower level of general antioxidant defense).

Silicon determination in human ventricular whole blood: a possible marker of drowning.

This article presents the first results demonstrating that total silicon trace concentration in human ventricular whole blood may be used as a further marker in the diagnosis of drowning. The difference in silicon content between the left and right ventricles was significantly higher for drowning cases than that from individuals who had not drowned. These findings were in full agreement with autoptic responses, supporting silicon as a marker of freshwater drowning. The procedure entails an alkaline microwave-assisted digestion using tetramethylammonium hydroxide (TMAH) in the presence of H(2)O(2) followed by dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS) detection, whose accuracy was obtained for Seronorm whole blood reference material. Satisfactory recoveries (91-98%) were gained on whole ventricular blood, with a silicon content lower than the method detection limit (MDL), spiked at 5 to 7µgg(-1) with materials consistent with drowning media constituents, that is, freshwater plankton (CRM [certified reference material] 414), silicon dioxide, diatomaceous earth powder, and a silicon standard solution. Good within-lab reproducibility (4-10%) and sensitivity (MDL=0.46µgg(-1)) were achieved as well. The procedure was applied to blood samples from 18 different real cases of death.

The comparative absorption of silicon from different foods and food supplements.

Dietary Si (orthosilicic acid; OSA) appears important in connective tissue health, and although the sources and intakes of Si are well established, its absorption is not. Si absorption was measured from eight high-Si-containing sources: alcohol-free beer; OSA solution (positive control); bananas; green beans; supplemental choline-stabilised OSA (ChOSA); supplemental monomethyl silanetriol (MMST); supplemental colloidal silica (CS); magnesium trisilicate British Pharmacopoeia antacid (MTBP). Two of the supplements and the antacid were pre-selected following an in vitro dissolution assay. Fasting, healthy subjects (CS, n 3; others, n > or = 5) each ingested two of the sources separated by a 1-week wash-out period. Blood and urine were collected and measured for total Si concentrations by inductively coupled plasma optical emission spectrometry. Absorption, based on urinary Si excretion, was highest for MMST and alcohol-free beer (64% of dose), followed by green beans (44%), OSA (43%), ChOSA (17%), bananas and MTBP (4%) and CS (1%). Peak serum concentrations occurred by 0.5 h for MMST and green beans, 1.5 h for OSA and alcohol-free beer, 2 h for ChOSA and CS, and 4 h for MTBP. Area under the serum curves correlated positively with urinary Si output (r 0.82; P < 0.0001). Absorption of Si from supplements and antacids was consistent with their known chemical speciation and kinetics of dissolution under simulated gastrointestinal conditions. Monomeric silicates were readily absorbed, while particulate silicates were decreasingly well absorbed with increasing polymerisation. The present results highlight the need to allow for relative absorption of Si from different foods or supplements in subsequent epidemiological and intervention studies.

Correlations among plasma silicon, magnesium and calcium in patients with knee osteoarthritis - analysis in consideration of gender.

INTRODUCTION AND OBJECTIVE: Osteoarthrits (OA) is a complex, chronic disorder of cartilage and bone, related to homeostasis of bioelements. The current study aimed at evaluation of correlations between plasma silicon, magnesium and ionized calcium in OA patients in consideration to gender. MATERIAL AND METHODS: The study comprised 59 patients aged 69.5±9.0 years (18 males aged 66.8±9.2; 41 females aged 70.7±8.8), admitted to the Trauma and Orthopaedic Ward of the Independent Public Health Care Centre in Leczna, Poland, due to OA and qualified to surgery. Control group consisted of 19 subjects without OA (54.5±8.6 years; 10 males aged 41.3±9.3; 9 females aged 69.1±14.9). Plasma concentrations of silicon and magnesium (spectrophotometric methods) and ionized calcium (potentiometric method) were determined. RESULTS: Silicon in OA patients was significantly increased vs. control. In OA males and OA females, silicon was enhanced vs. the respective controls, but it was statistically significant only in males. Magnesium in OA patients was not significantly different from control group. In females, a significant decrease vs. the respective control was observed. No significant differences were observed in the case of ionized calcium. Positive correlations between silicon and magnesium in healthy control, both in the whole group and in male and female subgroups, were noted, while no such effect was observed in OA subjects. CONCLUSIONS: The results might suggest some connection between higher OA incidence in women and the depleted magnesium in the organism. Silicon increase in OA patients, especially in men, may indicate its intense metabolism during the articular inflammatory process, likely dependent on sex hormones. It remains open whether the plasma Si increase is the effect or cause of OA.

Dietary Silicon and Its Impact on Plasma Silicon Levels in the Polish Population.

Silicon in nutritional amounts provides benefits for bone health and cognitive function. The relationship between silicon intake from a common daily diet and silicon blood level has been scarcely elucidated, so far. The aim of this study was to analyze the associations between plasma silicon levels and the total and bioavailable silicon intake-along with the contribution of silicon made by food groups-in a healthy adult Polish population. Si intake was evaluated in 185 healthy adults (94 females and 91 males, aged 20-70) using a 3-day dietary recall and a database on the silicon content in foods, which was based on both previously published data and our own research. Fasting plasma silicon levels were measured in 126 consenting subjects, using graphite furnace atomic absorption spectrometry. The silicon intake in the Polish population differed significantly according to sex, amounting to 24.0 mg/day in women and 27.7 mg/day in men. The median plasma silicon level was 152.3 µg/L having no gender dependency but with a negative correlation with age. Significant correlations were found between plasma silicon level and total and bioavailable silicon intake, as well as water intake in the diet (r = 0.18, p = 0.044; r = 0.23, p = 0.011; r = 0.28, p = 0.002, respectively). Silicon intakes from non-alcoholic beverages, cereal foods, and carotene-rich vegetables were also positively associated with plasma silicon levels. These results may help establish dietary silicon recommendations and formulate practical advice on dietary choices to ensure an appropriate supply of silicon. The outcome of this study, however, needs to be confirmed by large-scale epidemiological investigations.

Silicon intake and plasma level and their relationships with systemic redox and inflammatory markers in rheumatoid arthritis patients.

BACKGROUND: The nutritional significance of silicon for the human body is highlighted by a continually growing body of evidence. In conditions of excessive reactive oxygen species and upregulated immune response, silicon has been observed to provide benefits, but its role in redox and inflammatory status has not yet been examined in rheumatoid arthritis (RA). OBJECTIVES: The aim of this study was to assess the relationship of silicon intake and plasma level to systemic indices of redox status and inflammation in patients with RA. MATERIAL AND METHODS: Silicon intake and plasma levels were measured in 115 RA subjects and 129 control subjects. Serum antioxidant and oxidant levels, antioxidant enzyme activity, and albumin, uric acid, TBARS, hs-CRP, and IL-6 levels were measured and compared to the intake and plasma levels of silicon. RESULTS: Silicon intake and plasma silicon levels were higher in RA subjects than in the controls. In the RA group, a generally favorable correlation to redox and inflammatory markers was found for silicon in diet and in plasma; however, albumin level, smoking status, and gender interfered with these results. In the control subjects, a significant relationship was observed only between plasma silicon and non-enzymatic markers of redox status. CONCLUSIONS: There are suggestions of silicon's involvement in managing redox and inflammatory status in RA, though further studies are warranted.

Role of beer as a possible protective factor in preventing Alzheimer's disease.

Aluminium (Al), a neurotoxin, has lately been implicated as one of the possible causal factors contributing to Alzheimer's disease. Because silicon (Si) intake can affect the bioavailability of aluminium, the object of the present study was to assess whether moderate beer consumption might, as a source of dietary Si, affect the toxicokinetics of Al and thereby limit that element's neurotoxicity. The results obtained confirmed that at moderately high levels of beer intake the Si present in the beer was able to reduce Al uptake in the digestive tract and thus was able to slow the accumulation of this metal in the body, brain tissue included. In consequence, moderate beer consumption, due to its content in bioavailability silicon, possibly affording a protective factor for preventing Alzheimer's disease, could perhaps be taken into account as a component of the dietary habits of the population.

Bioavailability of a novel form of silicon supplement.

In this study, we assessed uptake and potential efficacy of a novel, pH neutral form of silicon supplement in vitro and using broiler chickens as a model species. In vitro bioavailability of this supplement was significantly higher than other commercial supplements tested, all of which claim available silica content. To confirm bioavailability of the new supplement in vivo, a broiler chick feeding trial reported blood uptake that was significantly higher than a Bamboo-derived silicon supplement. We assessed dose response of the novel supplement in a further study with increased dose related levels of silicon being detected in the blood and tibia. We found tibia and foot ash residue as a percentage of dry mass was higher with inclusion of the novel supplement in the diet, particularly in young birds and that this was followed by significant increase in tibia breaking strength. This novel supplement may therefore have applications in the improvement of bone integrity, with implications for the reduction of lameness in broilers. These results indicate the novel silica supplement is readily absorbed in chicks, and transported in the blood supply to sites such as the skeleton due to it being present in a non-condensed, monomeric form. There is potential for wider application of this silica supplement in other species where bone breakages are a problem, including high performance sport.

Metabolic effects of a novel silicate inositol complex of the nitric oxide precursor arginine in the obese insulin-resistant JCR:LA-cp rat.

Insulin resistance is a major contributor to macro- and microvascular complications, particularly in the presence of the metabolic syndrome, and is also associated with polycystic ovary syndrome. Impaired nitric oxide metabolism and endothelial function are important components of the vascular disease. Increasing the bioavailability of arginine, the precursor of nitric oxide, thus potentially offers protection against end-stage disease. We have recently demonstrated that dietary supplementation with a novel silicate inositol arginine complex reduces vasculopathy and glomerular sclerosis in the insulin-resistant JCR:LA-cp rat. The objective of this study was to address the absorption of, and the underlying metabolic alterations caused by, the arginine silicate inositol complex and arginine HCl (as a reference agent) in obese insulin-resistant male and female JCR:LA-cp rats. Male and female rats were treated with the preparations at 1.0 mg/(kg d) (expressed as arginine HCl) from 8 to 12 and 12 to 18 weeks of age, respectively. Obese female, but not male, rats treated with the arginine silicate inositol complex showed a reduced rate of weight gain without concomitant reduction in food intake. Plasma silicon levels were raised very significantly in arginine silicate-treated rats, consistent with significant absorption of the complex. In male rats, arginine levels were elevated by treatment with arginine silicate only; and female rats responded to both preparations. Plasma concentrations of oxides of nitrogen in rats treated with the silicate complex showed a dimorphism, decreasing in male and increasing in female rats. Fasting insulin levels were elevated in male rats treated with the arginine silicate complex, whereas fasting and postprandial insulin levels were decreased in female rats. Furthermore, female, but not male, rats treated with either of the arginine preparations showed significant reductions in cholesterol, triglyceride, and phospholipid concentrations. We conclude that the arginine silicate inositol complex is absorbed efficiently, raising plasma arginine levels, and is more biologically effective than the free amino acid hydrochloride. This has different beneficial metabolic effects in both sexes of an animal model of insulin resistance and cardiovascular disease, consistent with reduction in end-stage disease.

Plasma lead, silicon and titanium concentrations are considerably higher in green sea turtle from the suburban coast than in those from the rural coast in Okinawa, Japan.

The purpose of this study was to compare the concentration of trace elements in the plasma of sea turtles that inhabited the suburban (Okinawa Main Island, n=8) and the rural coast (Yaeyama Island, n=57) in Okinawa, Japan. Particle induced X-ray emission allowed detection of 20 trace and major elements. The wild sea turtles in the suburban coast in Okinawa were found to have high concentrations of Pb, Si and Ti in the plasma when compared to the rural area but there were no significant changes in the Al, As and Hg concentrations. These results may help to suggest the status of some elements in a marine environment. Further, monitoring the plasma trace and major element status in sea turtles can be used as a bio-monitoring approach by which specific types of elements found here could indicate effects that are related to human activities.

The Influence of Lithium and/or Selenium Treatment on Homeostasis of Chosen Bioelements in Rats.

Lithium is widely used in medicine and the therapy is often long term. Apart from beneficial effects, its application can cause diverse side effects. The current study was performed with the aim of the evaluation of the effect of lithium and/or selenium administration on magnesium, calcium and silicon levels in rats. The study was performed on rats divided into four groups (six animals each): control-received saline, Li-received Li2CO3 (2.7 mg Li/kg b.w.), Se-received Na2SeO3·H2O (0.5 mg Se/kg b.w.), and Li+Se-received simultaneously Li2CO3 and Na2SeO3·H2O (2.7 and 0.5 mg Se/kg b.w.). The administration was performed in form of water solutions by a stomach tube once a day for 6 weeks. In the organs (liver, kidney, brain, spleen, heart, lung and femoral muscle), the concentrations of magnesium, calcium and silicon were determined. Lithium significantly increased Ca in the kidney, brain and spleen. Coadministration of selenium reversed this effect. No changes of magnesium in organs were observed. Silicon was affected only in spleen-an increase vs. control was observed in all studied groups. The beneficial influence of coadministration of selenium in case of calcium lets us suggest that an issue of its possible use as an adjuvant alleviating side effects in lithium-treated subjects is worth being continued.

Simvastatin Effect on Calcium and Silicon Plasma Levels in Postmenopausal Women with Osteoarthritis.

Postmenopausal women more often suffered from knee osteoarthritis and its pathogenesis still remains unclear. Calcium and silicon are significant elements involved in bone and joint metabolism, especially in older people. Cardiovascular diseases are common worldwide and simvastatin is the most prescribed drug in such population of patients. The purpose of this study was to evaluate the effect of simvastatin administration on calcium and silicon concentration in the plasma of postmenopausal women with osteoarthritis. Sixty postmenopausal mild hypercholesterolemic women (mean age 61.4 years, range 54-68) were enrolled. Thirty patients received simvastatin (20 or 40 mg/day) for at least 1 year before being enrolled (simvastatin "+" group). Control group consists of remaining 30 women (simvastatin "-"group). Silicon and calcium concentrations were measured spectrophotometrically. Plasma simvastatin level was determined 3 h after the drug administration using HPLC-UV-Vis. Calcium but not silicon level was significantly lower in patients receiving simvastatin in comparison with non-statin group (1.91 ± 0.32 vs. 2.33 ± 0.19 mmol/l, p < 0.05). A weak but significant positive correlation between plasma silicon and simvastatin levels (r = 0.3, p < 0.05) was observed; this may be due to the fact that simvastatin contains silicon dioxide as an inactive ingredient. The mean simvastatin concentration was 9.02 ng/ml. All hypotheses were verified at the significance level of p < 0.05. A statistically significant decrease in the plasma calcium concentration of postmenopausal women, treated with simvastatin suggests that simvastatin may play a role in calcium metabolism in postmenopausal women with osteoarthritis. Positive correlation of simvastatin concentration with silicon level in the plasma suggests that both might prompt the positive effect of osteoarthritis treatment.

Haematic silicon in drowning.

The aim of this paper was to evaluate silicon (Si) concentration in human whole ventricular blood as a further potential chemical marker in the diagnosis of drowning. We employed an acidic digestion for the extraction of soluble Si, and an alkaline digestion for the determination of total Si, including particulate matter, both arising from drowning medium. 29 suspected drowning situations, 24 in fresh water (Fw) and 5 in seawater (Sw), were examined. The difference in Si concentration between the left and right ventricular blood (Si ΔL-R) was measured and alkaline Si ΔL-R seems, indeed, a potentially significant complementary tool in the diagnosis of Fw drowning, because insoluble silicon fraction does not undergo hemo-dilution or hemo-concentration, and the ΔL-R is not affected by exogenous factors. In spite of the limited number of cases investigated, a good correlation was observed between the analytical results and the macro-microscopic autoptic findings.