silicon and Body-Weight

To evaluate dietary ingredients involved in cartilage and bone metabolism and their influence on osteochondrosis lesions in swine.. 80 crossbred gilts (mean initial weight, 39 kg).. Pigs (10 pigs/treatment) were fed a corn-soybean meal basal (control) diet or the basal diet supplemented with additional minerals (copper and manganese or silicon), amino acids (proline and glycine; a combination of leucine, isoleucine, and valine; or methionine and threonine), or fatty acids (provided by fish oil) for 84 days. Pigs were then slaughtered and the distal portion of the left femur was collected for determination of osteochondrosis lesions at the femoral condyle. After evaluation of external joint surfaces, the distal portion of the femur was sectioned to evaluate lesions in the growth plate and articular cartilage. Additionally, a cartilage specimen was obtained from the patella for analysis.. Pigs fed diets containing high amounts of methionine and threonine or the diet containing all additional ingredients had significantly lower total severity scores, compared with scores for pigs fed the control diet or a diet supplemented with fish oil. Pigs fed diets containing additional proline and glycine, copper and manganese, methionine and threonine, or all additional ingredients had significantly lower overall scores, compared with scores for pigs fed the control diet or a diet supplemented with fish oil.. Dietary manipulation decreased the severity of osteochondrosis lesions, compared with results for pigs fed a control diet. However, additional research on optimal concentrations and combinations of dietary components is needed.

Topics: Amino Acids; Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Body Weight; Cartilage; Copper; Female; Fish Oils; Manganese; Osteochondritis; Silicon; Swine Diseases

Avena sativa L. a cereal crop that is badly affected by several abiotic and biotic stresses. In the current study, silicon nanoparticles are used to mitigate the harmful effects of root rot disease caused by Rhizoctonia solani Kuhn on the growth of A. sativa. In vitro (Petri plates) and in vivo (pots experiment) were performed to measure the various physiological and biochemical parameters i.e. osmotic potential, chlorophyll, proline content, growth parameters, sugar, fresh and dry weight, and disease index. Results revealed that physiological and biochemical parameters were reduced under fungal stress with silicon nanoparticles treatment as compared to the control group. Si nanoparticles helped to alleviate the negative effects caused by fungus i.e. germination percentage upto 80%, germination rate 4 n/d, radical and plumule length was 4.02 and 5.46, dry weight 0.08 g, and relative water content was (50.3%) increased. Fungus + Si treatment showed the maximum protein content, i.e. 1.2 µg/g as compared to Fungus (0.3 µg/g) treated group. The DI was maximum (78.82%) when the fungus directly attacked the target plant and DI reduced (44.2%) when the fungus was treated with Si nanoparticles. Thus, silicon nanoparticles were potentially effective against the stress of R. solani and also used to analyze the plant resistance against fungal diseases. These particles can use as silicon fertilizers, but further studies on their efficacy under field conditions and improvement in their synthesis are still needed.

Topics: Avena; Body Weight; Silicon; Stress, Physiological

Because leg injuries produce welfare concerns and impact production for broilers, numerous interventions have been suggested as potential solutions. One mineral which may affect bone quality is silicon. The objective of this study was to determine if supplementing bioavailable silicon could affect bone morphology, mineralization, and strength without negatively influencing welfare and meat quality. Male broilers were raised from d 1 after hatching until 42 d of age and randomly assigned to treatment groups for silicon supplementation in water: Control (no supplement, C; n = 125), Normal (0.011 ml supplement/kg bodyweight, N; n = 125) and High (0.063 ml supplement/kg bodyweight, H; n = 125). Toe damage, footpad dermatitis, hock burn, and keel blisters were assessed on d 42. Blood samples were collected from wing veins for serum osteocalcin, pyridinoline cross-links, and mineral analysis. Clinical QCT scans and analysis were conducted immediately before four-point bending tests of tibias. Texture analysis was performed on cooked fillets. Silicon supplementation tended to increase daily water consumption in N and H as compared to C (P = 0.07). Footpad dermatitis and hock burn scores were higher in H than in N or C (P < 0.05 for both comparisons). Supplementation altered serum minerals (P < 0.001), but bone density, morphology, and strength measures were similar among groups. The highest level of supplementation in the current study on a kg bodyweight basis was above recommended intakes but below previous amounts demonstrating silicon's positive influence on bone, indicating that previously suggested minimum thresholds need to be reevaluated. Factors such as growth rate and mechanical loading likely play a greater role in developing bone quality than trying to supplement on top of good basic nutrition alone.

Topics: Amino Acids; Animal Feed; Animals; Body Weight; Bone and Bones; Bone Density; Chickens; Dietary Supplements; Male; Osteocalcin; Random Allocation; Silicon; Tomography, X-Ray Computed

Accumulated data suggests a positive effect of silicon on bone health; however, limited research exists on the silicon content of foods. To further the understanding of the relationship between dietary silicon intake and bone health, a food composition database of commonly consumed foods in Korea is required. For quantitative data on the intake levels of silicon, we analyzed the silicon content of 365 food items commonly consumed in Korea using inductively coupled plasma-atomic emission spectrometry following microwave-assisted digestion. To investigate the dietary silicon intake status and to examine the potential role of dietary silicon intake in the bone status of men, a total of 400 healthy Korean adult males aged 19-25 were observed for their diet intake and calcaneus bone density using the 24-h recall method and quantitative ultrasound, respectively. Clinical markers reflecting bone metabolism such as serum total alkaline phosphatase, N-mid osteocalcin, and type 1 collagen C-terminal telopeptide concentrations were also analyzed. Silicon intake of the subjects was estimated as 37.5 ± 22.2 mg/day. Major food sources of dietary silicon in the Korean male were cereal and cereal products (25.6 % of total silicon intake), vegetables (22.7 %), beverages and liquors (21.2 %), and milk and milk products (7.0 %). Silicon intake correlated positively with age, weight, energy intake, protein intake, calcium intake, and alcohol intake. After adjusted for age, weight, energy intake, protein intake, calcium intake, alcohol intake, smoking cigarettes, and regular exercise status, daily total silicon intake had no correlation with calcaneus bone density and the bone metabolism markers, but silicon intake from vegetables had a positive correlation with serum total alkaline phosphatase activity, a bone formation maker. These findings show the possible positive relationship between dietary silicon intake from vegetables and the bone formation of young adult males. Further investigation in a larger (Korean) population and correcting for additional nutritional confounders is required to confirm these findings.

Topics: Adult; Asian People; Body Height; Body Mass Index; Body Weight; Bone Density; Bone Development; Diet; Food Analysis; Humans; Male; Nutrition Surveys; Nutritional Status; Republic of Korea; Silicon; Spectrophotometry, Atomic; Young Adult

Silicon (Si) has important functional roles in plants, including resistance against herbivores. Environmental change, such as increasing atmospheric concentrations of CO

Topics: Animals; Atmosphere; Body Weight; Carbon Dioxide; Feeding Behavior; Food Chain; Gryllidae; Mantodea; Phalaris; Predatory Behavior; Silicon

Previous studies have suggested that silicon (Si) had positive effects on bone, but such benefits from Si may be dependent on calcium status. Also, several biochemical roles of Si in osteoblastic mineralization, the regulation of gene expression related to bone matrix synthesis, and the decrease in reactive oxygen species and pro-inflammatory mediators were reported, but these effects were mostly shown in cell culture studies. Hence, we tested the effect of Si supplementation on bone status and the gene expression related to bone metabolism and inflammatory mediators in young estrogen-deficient rats under calcium-replete condition (0.5 % diet). Results showed that 15-week supplementation of both high and very high doses of Si (0.025 and 0.075 % diet, respectively) could not restore the ovariectomy (OVX)-induced decrease of bone mineral density (BMD) of vertebrae, femur, and tibia. Also, several bone biochemical markers (ALP, osteocalcin, CTx) and mRNA expression of COL-I, RANKL, IL-6, and TNF-α in femur metaphysis were not significantly changed by Si in OVX rats. However, a very high dose (0.075 %) of Si supplementation significantly increased OPG expression and decreased the ratio of RANKL/OPG in mRNA expression comparable to that of sham-control animals. Taken together, Si supplementation did not increase BMD under calcium-replete condition but the decrease in the ratio of RANKL/OPG expression to the normal level suggests the possibility of a bone health benefit of Si in estrogen deficiency-induced bone loss.

Topics: Animals; Body Weight; Bone and Bones; Bone Density; Calcium; Dietary Supplements; Female; Ovariectomy; Rats; Rats, Wistar; Silicon

The use of biomaterials from laboratories to clinics requires exhaustive and elaborate studies involving the biodistribution, clearance, and biocompatibility of biomaterials for in vivo biomedical applications. This study aimed to evaluate the acute toxicity and biodistribution of intravenously administrated sub-micrometer mesoporous bioactive glass spheres (SMBGs) in mice. The lethal dose 50 (LD50) of SMBGs was higher than 250 mg/kg. The acute toxicity was evaluated at 14 days after intravenous injection of SMBGs at 20, 100 and 180 mg/kg in ICR mice. The mortality, coefficients of major organs, hematology data and blood biochemical indexes revealed the low in vivo toxicity of SMBGs at all doses. However, the histological examination showed lymphocytic infiltration and granuloma formation in hepatocyte and megakaryocyte hyperplasia in the spleen at high dose. The silicon content analysis using ICP-OES and TEM results indicated that SMBGs mainly distributed in the resident macrophages of the liver and spleen, and could be cleared from the body more than 2 weeks. These findings can be important for the toxicity assessment of sub-micrometer particles and the development of bioactive glass based drug delivery system for biomedical applications.

Topics: Animals; Body Weight; Glass; Injections, Intravenous; Lethal Dose 50; Male; Mice, Inbred ICR; Microscopy, Electron, Transmission; Microspheres; Organ Specificity; Porosity; Serum; Silicon; Spectrophotometry, Atomic; Tissue Distribution; Toxicity Tests, Acute; X-Ray Diffraction

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.. 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.. 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.. 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.. 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.

Topics: Administration, Oral; Animals; Body Weight; Bone Density; Dietary Supplements; Estradiol; Female; Male; Organosilicon Compounds; Osteocalcin; Silicon; Tibia

Dietary silicon has been positively linked with vascular health and protection against atherosclerotic plaque formation, but the mechanism of action is unclear.. 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.. 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).. 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.. 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.

Topics: Animals; Aorta; Apolipoproteins E; Atherosclerosis; Body Weight; Cholesterol, HDL; Cholesterol, LDL; Diet; Diet, High-Fat; Dietary Supplements; Disease Models, Animal; Endothelium, Vascular; Female; Mice; Mice, Inbred C57BL; Mice, Knockout; Plaque, Atherosclerotic; Silicon; Triglycerides

This study aimed to evaluate the acute toxicity of intravenously administrated amorphous silica nanoparticles (SNPs) in mice. The lethal dose, 50 (LD50), of intravenously administrated SNPs was calculated in mice using Dixon's up-and-down method (262.45±33.78 mg/kg). The acute toxicity was evaluated at 14 d after intravenous injection of SNPs at 29.5, 103.5 and 177.5 mg/kg in mice. A silicon content analysis using ICP-OES found that SNPs mainly distributed in the resident macrophages of the liver (10.24%ID/g), spleen (34.78%ID/g) and lung (1.96%ID/g). TEM imaging showed only a small amount in the hepatocytes of the liver and in the capillary endothelial cells of the lung and kidney. The levels of serum LDH, AST and ALT were all elevated in the SNP treated groups. A histological examination showed lymphocytic infiltration, granuloma formation, and hydropic degeneration in liver hepatocytes; megakaryocyte hyperplasia in the spleen; and pneumonemia and pulmonary interstitial thickening in the lung of the SNP treated groups. A CD68 immunohistochemistry stain indicated SNPs induced macrophage proliferation in the liver and spleen. The results suggest injuries induced by the SNPs in the liver, spleen and lungs. Mononuclear phagocytic cells played an important role in the injury process.

Topics: Animals; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Body Weight; Hydrodynamics; Immunohistochemistry; Injections, Intravenous; Lethal Dose 50; Mice; Mice, Inbred ICR; Nanoparticles; Organ Specificity; Particle Size; Silicon; Silicon Dioxide; Spectrophotometry, Atomic; Static Electricity; Tissue Distribution; Toxicity Tests, Acute

Silicon-deficiency studies in growing animals in the early 1970s reported stunted growth and profound defects in bone and other connective tissues. However, more recent attempts to replicate these findings have found mild alterations in bone metabolism without any adverse health effects. Thus the biological role of silicon remains unknown. Using a specifically formulated silicon-depleted diet and modern methods for silicon analysis and assessment of skeletal development, we undertook, through international collaboration between silicon researchers, an extensive study of long-term silicon depletion on skeletal development in an animal. 21-day old female Sprague-Dawley rats (n=20) were fed a silicon-depleted diet (3.2 microg Si/g feed) for 26 weeks and their growth and skeletal development were compared with identical rats (n=10) on the same diet but with silicon added as Si(OH)(4) to their drinking water (53.2 microg Si/g water); total silicon intakes were 24 times different. A third group of rats, receiving a standard rodent stock feed (322 microg Si/g feed) and tap water (5 microg Si/g water), served as a reference group for optimal growth. A series of anthropometric and bone quality measures were undertaken during and following the study. Fasting serum silicon concentrations and especially urinary silicon excretion were significantly lower in the silicon-deprived group compared to the supplemented group (P=0.03 and 0.004, respectively). Tibia and soft-tissue silicon contents did not differ between the two groups, but tibia silicon levels were significantly lower compared to the reference group (P<0.0001). Outward adverse health effects were not observed in the silicon-deprived group. However, body lengths from week 18 onwards (P<0.05) and bone lengths at necropsy (P

Topics: Animal Feed; Animals; Body Weight; Bone and Bones; Bone Density; Bone Development; Bone Remodeling; Chondrocytes; Female; Rats; Rats, Sprague-Dawley; Silicon; Tetracycline; Tibia; Tomography, X-Ray Computed

The objective of this study was to examine the importance of nutrient status of a diatom (Stephanodiscus minutulus) to the uptake of PCB congener #54 (2,2',6,6'-tetrachlorobiphenyl) and the subsequent transfer of PCB to a pelagic grazing zooplankton (Daphnia pulicaria). The algae, which were grown under different nutrient treatments, were then fed to a zooplankton to examine the subsequent food chain transfer of PCB. Algal cultures were grown for at least 2 weeks in a steady state condition in (1) non-limiting, (2) low-Si, (3) low-N or (4) low-P media. Steady state algal cultures were dosed with 0.2 microg L(-1) PCB and were sampled for PCB uptake after 24h. D. pulicaria were allowed to graze on these same cultures for 48 h before being analyzed for PCB body burdens. Low-Si (68% or 0.135 microg L(-1) of PCB) and low-P cultures (62%) had significantly higher percentage uptake of total PCB than the non-limiting (55%) or low-N (52%) treatments. When these values were divided by biochemical or elemental parameters, PCB per lipids (microg microg(-1)) had one of the lowest coefficients of variation (CV) across the four treatments, indicating their importance in PCB uptake. When equal biovolumes of the four different treatment cultures were fed to zooplankton, both the low-N (13.9 ng PCB mg wet weight(-1)) and the low-P (9.6 ng PCB mg wet weight(-1)) grazing D. pulicaria had significantly higher PCB per wet weight than the low-Si (5.6 ng PCB mg wet weight(-1)) and non-limited (2.6 ng PCB mg wet weight(-1)) grazing D. pulicaria. There were no significant differences between algal nutrient treatments in PCB per wet weight of zooplankton grazing on clean algal food in PCB contaminated media. This study indicates that uptake of PCB by phytoplankton can be significantly altered by nutrient availability which subsequently affects transfer to zooplankton, potentially through such responses as grazing rate and lipid assimilation.

Topics: Animals; Body Weight; Daphnia; Diatoms; Food Chain; Lipids; Nitrogen; Phosphorus; Polychlorinated Biphenyls; Silicon; Time Factors; Water Pollutants, Chemical

Evidence suggests that short-term animal exposures to synthetic amorphous silicas (SAS) and crystalline silica can provide comparable prediction of toxicity to those of 90-day studies, therefore providing the opportunity to screen these types of substances using short-term rather than 90-day studies. To investigate this hypothesis, the inhalation toxicity of three SAS, precipitated silica Zeosil 45, silica gel Syloid 74, and pyrogenic silica Cab-O-Sil M5 was studied in Wistar rats. Rats were exposed nose-only to concentrations of 1, 5 or 25mg/m(3) of one of the SAS 6h a day for five consecutive days. Positive controls were exposed to 25mg/m(3) crystalline silica (quartz dust), negative controls to clean air. Animals were necropsied the day after the last exposure or 1 or 3 months later. All exposures were tolerated without serious clinical effects, changes in body weight or food intake. Differences in the effects associated with exposure to the three types of SAS were limited and almost exclusively confined to the 1-day post-exposure time point. Silicon levels in tracheobronchial lymph nodes were below the detection limit in all groups at all time points. Silicon was found in the lungs of all high concentration SAS groups 1-day post-exposure, and was cleared 3 months later. Exposure to all three SAS at 25mg/m(3) induced elevations in biomarkers of cytotoxicity in bronchoalveolar lavage fluid (BALf), increases in lung and tracheobronchial lymph node weight and histopathological lung changes 1-day post-exposure. Exposure to all three SAS at 5mg/m(3) induced histopathological changes and changes in BALf only. With all three SAS these effects were transient and, with the exception of slight histopathological lung changes at the higher exposure levels, were reversible during the 3-month recovery period. No adverse changes were observed in animals exposed to any of the SAS at 1mg/m(3). In contrast, with quartz-exposed animals the presence of silicon in the lungs was persistent and toxicological effects differed from those seen with SAS both with regard to the type and severity as well as in the time-response profile. In quartz-exposed animals silicon in the tracheobronchial lymph nodes was below the detection limit but silicon was found in the lungs at comparable levels 0-, 1- and 3-months post-exposure. One-day post-exposure to quartz, elevations in biomarkers of cytotoxicity in BALf, increases in lung and tracheobronchial lymph node weight and histopathologic

Topics: Aerosols; Animals; Body Weight; Bronchoalveolar Lavage Fluid; Eating; Female; Hydroxyproline; Inhalation Exposure; Leukocyte Count; Lung; Male; Organ Size; Particle Size; Quartz; Rats; Rats, Wistar; Silicon; Silicon Dioxide

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.

Topics: Animals; Arginine; Blood Glucose; Body Weight; Eating; Female; Inositol; Insulin; Insulin Resistance; Lipids; Male; Nitric Oxide; Obesity; Rats; Rats, Inbred Strains; Silicates; Silicon

Both arginine and silicon affect collagen formation and bone mineralization. Thus, an experiment was designed to determine if dietary arginine would alter the effect of dietary silicon on bone mineralization and vice versa. Male weanling Sprague-Dawley rats were assigned to groups of 12 in a 2 x 2 factorially arranged experiment. Supplemented to a ground corn/casein basal diet containing 2.3 microg Si/g and adequate arginine were silicon as sodium metasilicate at 0 or 35 microg/g diet and arginine at 0 or 5 mg/g diet. The rats were fed ad libitum deionized water and their respective diets for 8 wk. Body weight, liver weight/body weight ratio, and plasma silicon were decreased, and plasma alkaline phosphatase activity was increased by silicon deprivation. Silicon deprivation also decreased femoral calcium, copper, potassium, and zinc concentrations, but increased the femoral manganese concentration. Arginine supplementation decreased femoral molybdenum concentration but increased the femoral manganese concentration. Vertebral concentrations of phosphorus, sodium, potassium, copper, manganese, and zinc were decreased by silicon deprivation. Arginine supplementation increased vertebral concentrations of sodium, potassium, manganese, zinc, and iron. The arginine effects were more marked in the silicon-deprived animals, especially in the vertebra. Germanium concentrations of the femur and vertebra were affected by an interaction between silicon and arginine; the concentrations were decreased by silicon deprivation in those animals not fed supplemental arginine. The change in germanium is consistent with a previous finding by us suggesting that this element may be physiologically important, especially as related to bone DNA concentrations. The femoral and vertebral mineral findings support the contention that silicon has a physiological role in bone formation and that arginine intake can affect that role.

Topics: Administration, Oral; Animals; Arginine; Body Weight; Bone Density; Diet; DNA; Drug Synergism; Femur; Male; Minerals; Organ Size; Rats; Rats, Sprague-Dawley; Silicates; Silicon; Spine; Tibia

The effect of silicon (Si) supplement on preventing bone mass loss induced by ovariectomy (OVX) in rats was investigated. Three groups of 15, 100-day-old female Wistar rats each, with a mean initial weight of approximately 260 g per animal, were selected for the present study. One of the experimental group consisting of 15 OVX rats was fed a diet supplemented with 500 mg of Si per kg of feed (Si + OVX). The other two groups consisting of 15 OVX and 15 sham-OVX rats did not receive these supplements. Morphometric (weight and length) and densitometric studies with dual-energy X-ray absorptiometry were performed on the whole femur and 5th lumbar vertebra of each animal 30 days after the experiment. The Si + OVX rats did not show a loss of bone mass induced by OVX at axial level (5th lumbar vertebra) or periphery (femur). Nonetheless, a significant increase (ANOVA with Bonferroni/Dunn post hocs test) of longitudinal development of the femur (P < 0.0001) was patent. These results, obtained through the measurements of axial and peripheral bones, warrant closer scrutiny in connection with the Si inhibitory effect on bone mass loss as well as the stimulatory effect on bone formation. Both actions, namely, inhibition of resorption and stimulation of formation, infer that Si may have a potential therapeutic application in the treatment of involutive osteoporosis.

Topics: Absorptiometry, Photon; Animals; Body Weight; Bone Density; Bone Development; Dietary Supplements; Female; Femur; Lumbar Vertebrae; Osteoporosis; Ovariectomy; Rats; Rats, Wistar; Silicon

Two experiments were conducted using completely randomized designs to study the bioavailability of Si from three sources to growing rats and turkeys fed semipurified diets. The basal diets were dextrose-egg albumin for rats and dextrose-casein for turkeys. The Si sources were tetraethylorthosilicate (TES), sodium silicate (NaSil), and sodium zeolite A (NaZA). Rats and turkeys were supplemented at 500 and 270 ppm Si, respectively, from each source. A control group of unsupplemented rats and turkeys was included in each experiment. In general, irrespective of Si source, Si supplementation slowed (p < 0.05 or p < 0.01) growth rates in both rats and turkeys. Although dietary Si supplementation reduced (p < 0.05) plasma Mg levels and liver Zn concentrations in rats, it increased (p < 0.05) plasma P and reduced (p < 0.05) plasma Cu levels in turkeys. Rats on TES had significantly slower (p < 0.05 or p < 0.01) growth rates (5-10%) than those on NaSil or NaZA. In rats, NaZA and TES reduced (p < 0.05) hemoglobin concentrations and plasma Zn, respectively. However, plasma Mg levels were higher (p < 0.05) in TES than NaSil- or NaZA-fed rats. The source of the dietary Si did not affect (p < 0.05) the organ weights of rats and their mineral concentrations. Turkeys on TES diets grew at a significantly faster (p < 0.05) rate (15%) than those on NaSil or NaZA diets during the first 2 wk of experimentation. However, after 4 wk, there were no significant(p > 0.05) differences in growth between the Si sources. In turkeys, NaZA increased (p < 0.05) hematocrit levels and plasma Mg levels. Turkeys on NaZA diets had larger (p < 0.05) hearts and livers than those on NaSil but not TES. Liver Mn content was higher (p < 0.05) in turkeys on NaSil than TES or NaZA. Heart Zn was lower (p < 0.05) in turkeys on NaSil than TES, but not NaZA.

Topics: Aluminum; Animals; Biological Availability; Body Weight; Diet; Female; Hemoglobins; Liver; Myocardium; Random Allocation; Rats; Rats, Sprague-Dawley; Silanes; Silicates; Silicon; Sodium; Temperature; Time Factors; Turkeys; Zeolites

In recent years, it has been demonstrated that oral aluminium (Al) exposure can produce growth retardation, delayed ossification and an increased incidence of foetal abnormalities in rats and mice. On the other hand, it has been also suggested that silicon may have a protective effect in limiting oral Al absorption. The aim of the present study was to assess whether dietary silicon could prevent against Al-induced maternal and developmental toxicity in mice. On gestation days 6-15, Al nitrate nonahydrate (398 mg/kg/day) was given by gavage to three groups of pregnant animals, which also received silicon in drinking water at concentrations of 0, 118 and 236 mg/l on days 7-18 of gestation. Three additional groups of pregnant mice received respectively: 270.6 mg/kg of sodium nitrate (gavage), and silicon in drinking water at 118 and 236 mg/l. Although silicon administration at 236 mg/l significantly reduced the percentage of Al-induced deaths, abortions and early deliveries, neither 118 nor 236 mg/l of silicon produced significant ameliorations on Al-induced foetotoxicity. Under the current experimental conditions dietary silicon was not effective in protecting against Al-induced developmental toxicity.

Topics: Abnormalities, Drug-Induced; Aluminum Compounds; Animals; Body Weight; Bone and Bones; Diet; Eating; Embryonic and Fetal Development; Female; Fetus; Kidney; Liver; Male; Mice; Nitrates; Organ Size; Pregnancy; Reproduction; Sex Ratio; Silicon; Survival Rate

A 3x3 factorial experiment was conducted to study the interactions between Cu and Si in growing turkeys fed a basal dextrose-casein semipurified diet supplemented at 0, 270, and 540 ppm Si, and 2, 8, and 75 ppm Cu levels of inclusion. There were no significant (p>0.05) Cu, Si, or Cu-Si interaction effects on turkey growth. However, there were significant (p<0.05) Si effects on hemoglobin concentrations, and Cu-Si interaction effects on hematocrit and plasma Mg levels (p<0.01). Plasma Ca, P, Zn, Cu, total cholesterol, and serum alkaline phosphatase activity were not affected (p>0.05) by Cu, Si, or Cu-Si interaction. Heart and liver weights were affected (p<0.05) by the Cu-Si interaction. In general, a 8-ppm Cu supplemental level prevented cardiac hypertrophy only in the presence of 270 or 540 ppm Si inclusion in the diets. There were significant (p<0.05) Cu effects on liver Cu and Mn and heart Zn concentrations, Si effects on liver Mn levels, and Cu-Si interaction on liver Zn concentrations. Within the 0- and 270-ppm Si groups, Cu-deficient turkeys (2 ppm Cu) had higher liver Zn levels but not within the 540-ppm Si group. The Cu-Si interaction did not affect (p>0.05) concentrations of Cu in the heart and liver tissues. It is postulated that the Cu-Si interactions demonstrated in this study could have profound implications on the cardiovascular and skeletal health of birds.

Topics: Animal Feed; Animals; Body Weight; Cholesterol; Copper; Hematocrit; Hemoglobins; Male; Organ Size; Silicon; Turkeys

One of the challenging issues in modern biomedical science is the increasing number of osteoporosis patients due to the expansion of elderly populations. Among aging-related pathogenic changes, alterations in bone function and skeletal pathogenesis is a particularly important issue of concern. Osteoporosis is one of the most serious bone-related pathogenic states, as it causes serious loss of quality of life. Alterations in estrogen levels in accordance with aging are one of the key risk factors for osteoporosis. Complexed estrogen actions on bones can be traced by analyzing bone mineral components, as those elements accumulate as mineral complexes, reflecting the context of multiple cellular reactions such as bone resorption/osteogenesis. We have analyzed bone trace element composition in ovariectomized (OVX-treated) Cynomolgus monkey models in this study. In order to gain insights into the effects of such defects on bone trace element composition, inductively coupled plasma atomic emissions spectrometry (ICP-AES) analysis was performed. Marked changes in bone trace element levels were found in vertebral bones of OVX-treated Cynomolgus monkeys. An assessment of these trace element spectra in OVX model animals is discussed. These results could provide useful markers for understanding the physiological states of bones in postmenopausal women.

Topics: Animals; Body Weight; Bone Density; Calcium; Disease Models, Animal; Estradiol; Female; Macaca fascicularis; Magnesium; Osteoporosis; Ovariectomy; Ovary; Phosphorus; Silicon; Sodium; Spectrophotometry; Spine; Sulfur; Trace Elements; Zinc

The bioavailability of silicon in stabilized orthosilicic acid was investigated in a double blind, placebo controlled supplementation study of calves maintained on a normal diet. The total dietary Si intake was increased by 4.9% in the form of stabilized orthosilicic acid. After 23 wk of Si supplementation, the serum Si concentration increased (p = 0.0001, n = 29) by 70% compared to control animals in spite of the low Si dose administered and the Si adequate diet. The individually administered Si dose was significantly associated with the serum Si concentration (r = 0.44, p = 0.016, n = 29). The collagen concentration in dermis was significantly higher (p = 0.019, n = 4) in the Si group and a positive correlation (r = 0.72, p = 0.018, n = 9) was found between the Si concentration in serum and the collagen concentration in cartilage. The calcium (Ca) and phosphorus (P) concentrations in serum were marginally higher for animals supplemented with Si compared to control animals. In serum, a significant linear relationship was found between the Si and the Ca concentration (r = 0.31, p = 0.019, n = 59), whereas the magnesium concentration correlated marginally with the Si concentration (r = 0.25, p = 0.068, n = 59). In summary, increasing the total dietary Si intake by 4.9% in the form of stabilized orthosilicic acid resulted in a 70% higher Si concentration in serum indicating a high bioavailability of Si in this supplement. The positive correlation between the serum Si concentration and the collagen concentration in cartilage and the serum Ca concentration, respectively, suggest the involvement of Si both in the formation of extracellular matrix components and in Ca metabolism.

Topics: Animals; Body Height; Body Weight; Calcium; Cartilage; Cattle; Collagen; Double-Blind Method; Drug Stability; Food, Fortified; Growth; Hydroxyproline; Magnesium; Milk; Phosphorus; Silicic Acid; Silicon; Skin

A 2 x 2 x 2 factorial experiment was conducted using two dietary levels each (mg/kg of diet) of silicon, 0 and 500; iron, 35 and 187; and ascorbic acid, 0 and 900, to identify biochemical interactions occurring among these nutrients. Supplemental silicon, in conjunction with the higher dietary-iron level, prevented the plasma-iron decreasing effect observed for the higher level of iron in the absence of silicon. In the absence of ascorbic acid, silicon also increased iron concentration in the liver. Lower growth of the silicon and iron-supplemented rats is believed to be a response to a subsequent iron-imposed aberration of copper or zinc metabolism. This is supported by decreased intestinal metallothionein, increased weights (g/100 g body weight) of liver, heart, and testes, and decreased packed-cell volume and hemoglobin concentration. The lower plasma-iron level associated with the higher level of dietary iron appeared to be an expression of the iron-imposed reduction of liver copper stores. Ascorbic acid decreased plasma-iron concentration and prevented the silicon-related increase in liver iron.

Topics: Animals; Ascorbic Acid; Body Weight; Copper; Diet; Iron; Male; Organ Size; Rats; Rats, Sprague-Dawley; Silicon; Zinc

The chemical properties of Ge are similar to Si. This study investigated whether Ge can substitute for, or is antagonistic to, Si in bone formation. Sixty male weanling Sprague-Dawley rats were randomly assigned to treatment groups of 12 and 6 in a 2 x 4 factorially arranged experiment. The independent variables were, per gram fresh diet, Si (as sodium metasilicate) at 0 or 25 micrograms and Ge (as sodium germanate) at 0, 5, 30, or 60 micrograms. Results confirmed that Ge does not enhance Si deprivation and provided evidence that Ge apparently can replace Si in functions that influence bone composition. When Si was lacking in the diet, calcium and magnesium concentrations of the femur were decreased; this was reversed by feeding either Ge and/or Si. Similar effects were found for zinc, sodium, iron, manganese, and potassium of vertebra. There were some responses to Si deprivation that Ge could not reverse; Ge did not increase femur copper, sodium, or phosphorus or decrease molybdenum of vertebra, effects that were evoked by Si supplementation. Additionally, some findings suggested that 60 micrograms Ge/g diet could be a toxic intake for the rat. On the other hand, some responses induced by Ge indicate that this element may be acting physiologically other than as a substitute for Si. Germanium itself affected bone composition. Germanium supplementation decreased Si and molybdenum in the femur and increased DNA in tibia. Regardless of the amount of Si fed, animals fed 30 micrograms Ge/g diet had increased tibial DNA compared to animals fed 0 or 60 micrograms Ge; however, tibial DNA of animals fed 30 micrograms Ge was not statistically different from those animals fed 5 micrograms Ge. Thus, Ge may be of nutritional importance.

Topics: Animals; Blood Proteins; Body Weight; Bone and Bones; Calcification, Physiologic; Copper; Diet; DNA; Germanium; Kidney; Male; Organ Size; Random Allocation; Rats; Rats, Sprague-Dawley; Silicon; Tibia; Zinc

Two 8-wk experiments were conducted with Sprague-Dawley weanling rats to determine whether interactions occurring between Zn and Si, or a nutritional deficiency of either Cu or Zn, affect silica urolith formation. In Exp. 1, concentrations of 0, 540, and 2,700 mg of Si/kg of diet from tetraethylorthosilicate were used with dietary Zn concentrations of 4, 12, and 500 mg/kg of diet in a 3 x 3 factorial arrangement. In Exp. 2, copper at 1 or 5 mg/kg of diet and Zn at 4, 12, and 500 mg/kg of diet were used in a 2 x 3 factorial arrangement. All diets in Exp. 2 contained 2,700 mg of Si/kg. Silica uroliths occurred in all treatments providing, 2,700 mg of Si/kg of diet. There was a trend (P = .17) toward a reduction of silica urolith incidence with increasing concentrations of dietary Zn in Exp. 1. In Exp. 2, a deficiency of Zn, and a Cu deficiency exacerbated by 500 mg of Zn/kg of diet, increased (P < .05) silica urolith formation. An antagonism between Si and Zn, as demonstrated previously in the rat, may not be of a sufficient magnitude to be applicable to the prevention of silica urolithiasis. The data further demonstrate that Zn deficiency and, to a lesser extent, Cu deficiency contributed to silica urolith formation in rats fed diets having a high content of absorbable Si. However, 540 mg of Si/kg of diet may potentiate the metabolic activity of Zn, as indicated by a 23% Si-mediated weight gain response in Zn-deficient rats.

Topics: Alkaline Phosphatase; Animals; Body Weight; Calcium; Copper; Disease Models, Animal; Magnesium; Male; Phosphorus; Rats; Rats, Sprague-Dawley; Silicon; Silicon Dioxide; Urinary Calculi; Zinc

Female rats received an ip injection of aluminum chloride (10 mg Al/kg/d) during the first 12 d after parturition; this treatment led to a reduction in food intake associated with a reduction in body wt. Pups of the intoxicated dams showed a growth retardation after postnatal day 7. One day after treatment, the female rats intoxicated with aluminum had a considerably higher level of aluminum in milk than controls. The aluminum levels of plasma, liver, spleen, and kidneys were also significantly higher in treated female rats than controls. On the contrary, in the same tissues of pups from treated or not treated dams, no differences in aluminum levels were observed. No effect of aluminum treatment was detected on plasma silicon levels in dams and pups.

Topics: Aluminum; Aluminum Chloride; Aluminum Compounds; Animals; Animals, Newborn; Biological Transport; Body Weight; Chlorides; Eating; Female; Lactation; Liver; Male; Milk; Organ Size; Rats; Rats, Wistar; Silicon; Tissue Distribution

The therapeutic effects of mercaptopurine (6-mercaptopurine, 6-MP) and a silylated derivative (6-trimethylsilylthio-9-trimethyl-silylpurine, S-MP) were compared on the course of T lymphocyte line mediated experimental allergic encephalomyelitis (t-EAE). This transferred EAE is a passively induced model disease in Lewis rats easy to elicit, reliably reproducible and characterized by a dose-dependent lethality. If given at different points in single injections the silicon derivative is shown to be more efficient than 6-MP (43/125 surviving animals compared to 26/129), severity of disease is attenuated and number of survivors increased. Silylation is able to improve blood-brain barrier and cellular permeability; S-MP suppresses intrathecal inflammatory cells more effectively than the original immunosuppressant.

Topics: Animals; B-Lymphocytes; Blood-Brain Barrier; Body Weight; Cell Membrane Permeability; Encephalomyelitis, Autoimmune, Experimental; Female; Mercaptopurine; Rats; Rats, Inbred Strains; Silicon; T-Lymphocytes; Trimethylsilyl Compounds

Sprague-Dawley rats were exposed 6 hr/day, 5 days a week, for 28 days to tetramethoxysilane (TMOS) at concentrations of 0, 1, 5, and 10 ppm (Phase I study) and to 0, 15, 30, and 45 ppm (Phase II study). All of the rats exposed to 45 ppm TMOS died or were sacrificed in a moribund state during the 28-day study period. Statistically significant changes were observed in food consumption, body weights, and clinical chemistry parameters in the animals exposed to 30 ppm TMOS. Males exposed to 15 ppm TMOS showed a significant decrease in total protein. No effects were seen in rats exposed to 1, 5, and 10 ppm TMOS. Histopathological lesions related to TMOS exposure were observed in the respiratory tract tissues and eyes of rats exposed to 15, 30, and 45 ppm TMOS. The principal types of lesions observed were ulceration, inflammation, and necrosis of epithelium. At 45 ppm, changes at these sites were severe and present in all animals. Changes at 30 ppm, while occurring in all rats, were much less severe than those seen at 45 ppm. At 15 ppm, the changes were minimal and occurred only in three males and five females. The data of this study showed that TMOS has a steep dose-response curve with no observable effects at 10 ppm, very minimal effects at 15 ppm, moderate to severe effects at 30 ppm, and severe effects and lethality at 45 ppm.

Topics: Administration, Inhalation; Air Pollutants, Occupational; Animals; Blood Chemical Analysis; Body Weight; Cornea; Eating; Female; Inflammation; Male; Nasal Mucosa; Organ Size; Rats; Rats, Inbred Strains; Silanes; Silicon

beta-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ECEMS, CAS No. 3388-04-3) is mutagenic in vitro and weakly carcinogenic in mice after dermal application. Timed pregnant Fischer 344 rats and New Zealand white rabbits were dosed with ECEMS in corn oil by gavage on gestational days (gd) 6 through 15 at doses of 0.0, 0.25, 1.0, or 2.5 ml ECEMS/kg for rats and 0.0, 0.05, 0.25, or 0.75 ml ECEMS/kg for rabbits. At termination on gd 21 (rats) or gd 29 (rabbits), live fetuses were examined for external, visceral, and skeletal alterations. In rats, maternal toxicity was observed at 1.0 and 2.5 ml/kg, as evidenced by reduced weight gain and food consumption during treatment, clinical signs of toxicity, reduced body weight on gd 21 (corrected for gravid uterine weight), and increased relative liver weight. There were no significant differences among groups on pre- or postimplantation loss, fetal body weight/litter, or on the incidence of malformations. Minimal fetal toxicity, dilated lateral cerebral ventricles and reduced ossification in the forelimbs, was observed at 2.5 ml/kg. In rabbits, maternal mortality (2/20 does) and slightly (but statistically significantly) elevated maternal relative kidney weight were observed at 0.75 ml/kg. Clinical signs of toxicity were observed at 0.25 and 0.75 ml/kg. Pre- and postimplantation loss, fetal body weight/litter, and the incidence of malformations were all unaffected by treatment. Minimal fetal toxicity, extra (13th) ribs and reduced ossification in lumbar arch 4, was observed at 0.75 ml/kg ECEMS. Therefore, administration of ECEMS during organogenesis in rats and rabbits produced maternal toxicity at 1.0 and 2.5 ml/kg in rats and at 0.25 and 0.75 ml/kg in rabbits. Minimal fetal toxicity was observed at 2.5 ml/kg in rats and at 0.75 ml/kg in rabbits. No embryotoxicity or teratogenicity was observed in either species at any dosage. The "no observable effect level" (NOEL) for maternal toxicity was 0.25 ml/kg for rats and 0.05 ml/kg for rabbits; the NOEL for developmental toxicity was 1.0 ml/kg for rats and 0.25 ml/kg for rabbits.

Topics: Adhesives; Animals; Body Weight; Eating; Female; Fetus; Gestational Age; Male; Organ Size; Pregnancy; Rabbits; Rats; Rats, Inbred F344; Silanes; Silicon; Teratogens

Three experiments were conducted to determine the effects of excess dietary calcium carbonate, phosphorus and urine acidifying and alkalizing salts on silica urolith formation in a model using rats fed dextrose-based diets containing 2% tetraethylorthosilicate (TES). Diets containing 2% TES lowered weight gains to 91-95% of gains made by rats fed non-TES diets. Urine silica concentrations of rats fed TES were generally in the range of 50-60 mg/dl. In experiment 1, rats fed TES with no additional dietary calcium carbonate had a silica urolith incidence of 35%. With additions of 1 and 2% calcium carbonate to the basal-TES diet, respective urolith incidences were 45 and 60% (r = 0.99, P less than 0.02). In experiment 2, monobasic sodium phosphate (MP) providing 0.2% additional phosphorus resulted in a mean urine pH of 6.42 and no uroliths. Dibasic sodium phosphate (DP) without and with 0.5% sodium bicarbonate (SB) resulted in respective urine pH values of 6.78 and 7.14 and urolith incidences of 15 and 20% (MP less than DP and DP + SB, P less than 0.05). However, the uroliths were small averaging less than 1 mg. In experiment 3, substitution of autoclaved egg albumin for casein, the protein source in experiments 1 and 2, resulted in urine pH of 7.45 and a silica urolith incidence of 46%. An equal-molar mixture of MP and DP providing an added 0.2% phosphorus resulted in a urine pH of 7.07 and reduced the urolith incidence to 4%, and 0.75% of dietary ammonium chloride either with or without the added 0.2% phosphorus gave urine acidification and complete protection from uroliths.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Administration, Oral; Animals; Bicarbonates; Body Weight; Calcium; Calcium Carbonate; Carbonates; Diet; Drug Interactions; Hydrogen-Ion Concentration; Magnesium; Male; Phosphorus; Rats; Rats, Inbred Strains; Silanes; Silicon; Silicon Dioxide; Sodium; Sodium Bicarbonate; Urinary Calculi

Rats were exposed by inhalation to 5 or 50 mg/m3 Mount St. Helens volcanic ash, to 50 mg/m3 quartz (positive controls), or to filtered room air (sham-exposed controls), for 6 hr/day, 5 days/week, for up to 24 months to investigate biological effects of chronic inhalation exposure to volcanic ash under controlled laboratory conditions. Exposure-related lung changes comprised accelerated respiratory frequency; alveolar macrophage accumulation; interstitial reaction; lymphoreticular reaction in peribronchiolar regions and in mediastinal lymph nodes; alveolar proteinosis in the 50- mg/m3 ash- or quartz-exposed groups; increase in fresh lung weights; decreased body weight and increased mortality in the quartz-exposed group; and epidermoid carcinomas especially in the quartz-exposed females and, to a lesser extent, in the 50-mg/m3 ash-exposed females. The observed changes reflect significant dose-response and agent-response relationships.

Topics: Aerosols; Air Pollutants; Animals; Atmosphere Exposure Chambers; Body Weight; Carbon; Female; Lung; Male; Quartz; Rats; Rats, Inbred F344; Respiration; Silicon

An animal inhalation study was initiated to study the chronic biological effects of inhalation of short chrysotile asbestos fibers. Rats and monkeys were exposed for 18 months, 7 hr/day, 5 days/week to a specially prepared, chrysotile asbestos aerosol. Based upon daily chamber measurements, the mean concentration of fibers in the chamber air was 1.0 mg/m3. By phase contrast microscopy, the number of fibers greater than 5 micron in length was determined to be 0.79 fiber per cubic centimeter. Rats were autopsied for pathological and histochemical examination at 1, 3, 6, 12, 18, and 24 months after initiating exposures. No significant differences in the histochemical data were seen between the exposed and control groups. Gross and histopathologic examination of exposed and control groups of rats indicated no compound-related lesions, including fibrosis. Open lung biopsies were performed on the chrysotile-exposed and the control monkeys 28 months after initiating exposures. Histopathologic evaluation of the lung biopsy tissue showed the presence of asbestos bodies adjacent to the terminal bronchioles of the asbestos-exposed monkeys. There was no observed fibrosis in pulmonary tissue. All monkeys are being maintained for an indefinite period and observed for signs of latent pulmonary disease.

Topics: Aerosols; Animals; Asbestos; Asbestos, Serpentine; Body Weight; Dust; Lung; Lung Diseases; Macaca fascicularis; Male; Microscopy, Electron, Scanning; Organ Size; Particle Size; Rats; Rats, Inbred Strains; Silicon; Species Specificity; Time Factors

The embryotoxic and teratogenic potential of gamma- glycidoxypropyltrimethoxysilane ( GPTS ) was evaluated in rats. Pregnant Sprague-Dawley rats were administered 0, 50, 500, or 1,000 mg/kg/day of GPTS by gavage on days 6 through 15 of gestation. No treatment related signs of toxicity, behavioral alterations or mortalities were observed in any of the pregnant animals. There was no evidence of adverse effects in mean maternal body weight, liver weight or food consumption of the treated females. The number of implantation sites, number of live fetuses per litter, the mean litter size, the sex ratio, the fetal body weight or the crown-rump length were not affected by treatment. The incidence of resorptions among the total fetal population was not altered by the administration of GPTS to pregnant rats, indicating that the test material is not embryolethal in rats at the tested dose levels. Few scattered incidences of fetal alterations in the external, soft tissue or skeletal examinations were seen both among treated and untreated litters, however, no single alteration was observed in treated litters at an incidence which was significantly different from the control. In conclusion GPTS was not embryotoxic or teratogenic in rats at dose levels up to 1000 mg/kg/day.

Topics: Abnormalities, Drug-Induced; Animals; Body Weight; Bone and Bones; Female; Male; Pregnancy; Rats; Rats, Inbred Strains; Silanes; Silicon

The subchronic toxicity (28 days) of orally administered gamma-Glycidoxypropyltrimethoxysilane (GPTS) was studied in laboratory rats. The test material was administered daily for four weeks to groups of 10 male and 10 female Sprague-Dawley rats by gavage at dose levels of 0, 40, 400, and 1,000 mg/kg. Mortality, behavioral reactions, growth and food consumption were observed and measured along with hematology, blood biochemistry, absolute and relative organ weights. No overt signs of toxicity or behavioral abnormalities were observed in any of the test animals during the course of the study. There were no treatment related mortalities and no significant differences were observed in mean body weight, food consumption, absolute or relative organ weights of control and treated rats. Also, there were no meaningful differences in hematology, urinalysis or clinical blood chemistry values between control and treated animals. Gross and histopathologic examinations of organs or tissues from both control and GPTS treated animals did not reveal any treatment related changes. These results suggest that it is unlikely that serious injury would result from the ingestion of GPTS in amounts normally encountered incidental to its industrial use.

Topics: Animals; Body Weight; Fasting; Female; Male; Organ Size; Rats; Rats, Inbred Strains; Sex Factors; Silanes; Silicon; Time Factors

Topics: Animals; Antigens, Bacterial; Body Weight; Dust; Environmental Exposure; Escherichia coli; Female; Hemolytic Plaque Technique; Immunity; Lung; Mice; Mice, Inbred BALB C; Silicon; Silicosis; Spleen

Studies were undertaken to determine further effects of silicon deficiency in the chick. The diet and experimental conditions were the same as those used in previous studies to demonstrate the essentiality of silicon for growth and development. Skeletal and other abnormalities involving glycosaminoglycans in formation of articular cartilage and comb connective tissue were found to be associated with silicon deficiency. The bones of 1 day-old deutectomized cockerels fed a silicon supplemented diet and killed at 4 weeks of age had significantly greater amounts of articular cartilage and water as compared with the silicon deficient group and also a greater proportion of hexosamine in the cartilage. The greater water content in bones of the silicon supplemented chicks coincided with a larger content of glycosaminoglycans in the articular cartilage. A similar relationship was obtained in cockerel comb. In addition to larger amounts of connective tissue and of total hexosamine in combs of the supplemented group, a higher percentage of hexosamine and a higher silicon content was found. These findings provide the first evidence for a requirement for silicon in articular cartilage and connective tissue formation and that the site of action of silicon is in the glycosaminoglycan-protein complexes of the ground substance.

Topics: Animals; Body Water; Body Weight; Bone and Bones; Chickens; Comb and Wattles; Connective Tissue; Femur; Glycosaminoglycans; Hexosamines; Male; Minerals; Nutritional Requirements; Proteins; Silicon; Tibia

Silicon is required for normal growth and development in the chick when a low silicon diet is fed in a trace element controlled environment. Day-old deutectomized cockerels fed a purified amino acid diet showed significantly retarded growth and development within 2 to 3 weeks. Chicks fed the same diet plus a silicon supplement showed 50 percent higher growth and normal development. Silicon meets the criteria for an essential trace element.

Topics: Animals; Body Weight; Chickens; Deficiency Diseases; Diet; Growth; Nutritional Requirements; Silicon; Trace Elements