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Effect of acidic primers on bonding three magnetic steel alloys with tri-n-butylborane initiated methacrylic resin.

The purpose of this study was to evaluate the effect of acidic primers on bonding magnetic steel alloys. Three alloys (XM27, 447J1, and AUM20) were primed with one of the following materials: Acryl Bond, Estenia Opaque Primer, Eye Sight Opaque Primer, M. L. Primer, or Super-Bond liquid. The specimens were bonded with a tri-n-butylborane initiated resin, and bond strength was determined both before and after thermocycling in water. Unprimed specimen was considered as the control. Average bond strength varied from 0 to 45.3 MPa for the XM27 alloy, 0.3 to 43.6 MPa for the 447J1 alloy, and 0.5 to 41.1 MPa for the AUM20 alloy. Of the five primers, Estenia Opaque Primer exhibited better adhesive performance than the other materials regardless of the type of steel alloy. It can be concluded that the use of the Estenia Opaque Primer, which contains an adhesive monomer (10-methacryloyloxydecyl dihydrogen phosphate; MDP), is recommended for bonding the three magnetic steel alloys with TBB-initiated resin.

Acid Etching, Dental↗

[Application of renal epithelial cell culture in study of organ toxicity of heavy metals].

To elucidate the possible toxicity of heavy metals in a renal tubular epithelial cell line derived from a normal cynomolgus female monkey (JTC-12, P3 (F], the effects of HgCl2, Na2CrO4 and NiCl2 on the dome formation and the release of intrinsic enzymes from the cells were studied. The results were as follows: 1. The JTC-12. P3(F) cells showed an evident dome formation when an inducer of differentiation (hexamethylene bisacetamide or N, N-dimethylformamide) was added to the medium. 2. Ouabain inhibited the dome formation of the JTC-12. P3(F) cells, suggesting that the dome formation is dependent on the active transepithelial transport of Na+. 3. The addition of 40 microM HgCl2, 10 microM Na2CrO4 or 20 microM NiCl2 inhibited the dome formation. 40 microM HgCl2, 10 microM Na2CrO4 or 150 microM NiCl2 caused significant cell death. 4. The addition of 5 microM HgCl2, 1 microM Na2CrO4 or 20 microM NiCl2 resulted in an increased release of lactate dehydrogenase into the medium for 6 hours. 20 microM HgCl2, 1 microM Na2CrO4 or 20 microM NiCl2 increased the medium gamma-glutamyl transpeptidase concentration for 6 hours, but 40 microM HgCl2, 5 microM Na2CrO4 or 100 microM NiCl2 did not cause a significant increase in the medium alkaline phosphatase concentration. The results suggest that the JTC-12. P3(F) cells possess, at least in part, functional characteristics similar to the other kidney proximal tubular cells and that the inhibition of dome formation and enzyme release from the cells may be the early indicators that predict metal toxicity to the cells.

Animals↗

Effects of neutral, cationic, and anionic chromium ascorbate complexes on isolated human mitochondrial and genomic DNA.

The relative activities of neutral, cationic, and anionic chromium ascorbate complexes toward isolated human mitochondrial and genomic DNA were investigated at physiologically relevant conditions by agarose gel electrophoresis. A direct relationship between the charge of the Cr(III) species and their DNA-damaging properties was found. The cationic species were found to be fully capable of DNA-cleavage, even in short incubation periods. Incubations were also performed in the presence of amino acids. No apparent effect was observed under the applied experimental conditions to facilitate or prevent damage through the ternary amino acid-Cr-DNA adduct formation or binary chromium-amino acid complex formation.

Amino Acids↗

Use of microwave digestion and atomic absorption spectrophotometry to determine chromic oxide as a digestibility marker in feed, feces, and ileal content.

Most conventional digestion procedures, such as dry ashing and wet ashing, are tedious and labor intensive. Microwave digestion is a good alternative, because microwave dissolution is faster, safer, and simpler, and provides more controlled reproducible conditions than conventional methods. The purpose of this study was to develop a microwave digestion method for mineralizing meat and bone meal diets, feces, and ileal contents. Each sample was heated on a hot plate for 10 min, dry ashed at 65 degrees C for 4 h, and transferred into microwave vessels. Then, 10 mL 70% HNO3 was added. Samples were digested for 7, 10, and 20 min at 95, 90, and 85% power, respectively. After the heating cycle, 6 mL 30% H2O2 was added, and samples were returned to the microwave for a second heating cycle of 1 and 7 min at 95% and 90% power, respectively. Finally, chromium concentration was determined by flame atomic absorption spectrophotometry. The digestion method was validated by using a standard reference material, SRM domestic sludge 2781, with a certified chromium value of 195 +/- 9 micrograms/g. The value obtained in this study was 178 +/- 11 micrograms/g, for a difference of 17 micrograms/g. Spike recovery experiments resulted in 103.16 and 100.35% recoveries of chromium from diet and feces samples, respectively. Coefficients of variation were 10.8 and 7.8%, respectively.

Animal Feed↗

Treatment of an aneurysmal bone cyst of the spine by radionuclide ablation.

We report the nonoperative treatment of a recurrent, multilevel spinal aneurysmal bone cyst by injection of 32P chromic phosphate colloid into the cyst. The patient was then followed up with serial CT examinations, which showed stabilization and progressive ossification within the lesion. The rationale, alternatives, and possible contraindications to radionuclide ablation of spinal aneurysmal bone cysts are discussed.

Adolescent↗

The effects of inorganic chromium and brewer's yeast supplementation on glucose tolerance, serum lipids and drug dosage in individuals with type 2 diabetes.

OBJECTIVE: To study the effects of supplementation with organic and inorganic chromium on glucose tolerance, serum lipids, and drug dosage in type 2 diabetes patients, in the hope of finding a better and more economical method of control. METHODS: Seventy eight type 2 diabetes patients were divided randomly into two groups and given Brewer's yeast (23.3ug Cr/day), and CrCl3 (200ug Cr/day) sequentially with placebo in between, in a double blind cross-over design of four stages, each lasting 8 weeks. At the beginning and end of each stage, subjects were weighed, their dietary data and drug dosage recorded, and blood and urine samples were collected for analysis of glucose (fasting and 2 hour post 75g glucose load) fructosamine, triglycerides, total and HDL-cholesterol, and serum and urinary chromium. RESULTS: Both supplements caused a significant decrease in the means of glucose (fasting and 2 hour post glucose load), fructosamine and triglycerides. The means of HDL-cholesterol, and serum and urinary chromium were all increased. The mean drug dosage decreased slightly (and significantly in case of Glibenclamide) after both supplements and some patients no longer required insulin. No change was noted in dietary intakes or Body Mass Index. A higher percentage of subjects responded positively to Brewer's yeast chromium, which was retained more by the body, with effects on fructosamine, triglycerides, and HDL-cholesterol maintained in some subjects when placebo followed it, and mean urinary chromium remaining significantly higher than zero time mean. CONCLUSION: Chromium supplementation gives better control of glucose and lipid variables while decreasing drug dosage in type 2 diabetes patients. A larger scale study is needed to help decide on the convenient chemical form, and dosage required to achieve optimal response.

Adult↗

[Effect of CrCl3 on the in vitro production of flavonoids in a culture of Ononis arvensis L].

The paper investigated the effect of the abiotic elicitor chromium trichloride on the production of flavonoids in the callus and suspension cultures of Ononis arvensis L. after 12; 24; 48; 72, and 168-hour administration. The tested elicitor positively influenced the formation of flavonoids. A statistically significant increase in the flavonoid production in the callus culture was recorded with the use of a chromium trichloride solution in the concentration c1 (6.32 x 10(-4) mol/l) after 24; 48; 72, and 168 hours, in the concentration c2 (6.32 x 10(-6) mol/l) after 24; 48, and 72 hours, and in the concentration c3 (6.32 x 10(-8) mol/l) after 12; 24, and 48 hours. In the suspension culture, the flavonoid production was significantly increased by the concentration c1 (6.32 x 10(-4) mol/l) after 12 and 72 hours, the concentration c2 (6.32 x 10(-6) mol/l) after 12; 24; 48, and 72 hours, and the concentration c3 (6.32 x 10(-8) mol/l) after 12; 24; 48, and 72 hours. The maximal increase in the flavonoid production by 98% took place in the callus culture after elicitation with a chromium trichloride in the concentration c3 (6.32 x 10(-8) mol/l) after 48 hours of administration, and in the suspension culture after elicitation with CrCl3 in the concentration c2 (6.32 x 10(-6) mol/l) after 12 hours by 100%.

Chlorides↗

In vitro push-out strength of seven luting agents to dentin.

PURPOSE: New luting agents, described as resin-modified glass-ionomer cements and compomers, have been developed during the last decade to improve the retention of cemented restorations. The aims of this study were to (1) compare the push-out strength of these new luting materials against both conventional cements and bonding luting agents, and (2) evaluate the influence of dentin surface treatment on both glass-ionomer cement and 4-META adhesive resin push-out strength. MATERIALS AND METHODS: Conical standardized cavities were drilled in the center of coronal dentin disks. Ninety sandblasted Ni-Cr inlays, divided into nine batches, were luted into the cavities according to the surface treatment and the nature of the following luting agents: zinc phosphate cement, zinc polycarboxylate cement, type 1 glass-ionomer +/- polyacrylic acid, resin-modified glass-ionomer, polyacid-modified composite resin, filled bis-GMA phosphate ester resin, and 4-META adhesive resin +/- application of activated monomer. Each specimen was placed in a holding device, and a steel rod was used to apply a force on the inlay until rupture occurred. The push-out strength was calculated, and the failure mode was controlled. RESULTS: There were significant differences between some of the groups. The highest push-out strength was achieved by the 4-META adhesive resin after application of activated monomer. The lowest value was attained with zinc phosphate and polycarboxylate cements. CONCLUSION: Both resin-modified glass-ionomer and polyacid-modified composite resin luting materials exhibited a push-out strength similar to resin-based materials. Specific dentin surface treatments significantly enhanced the push-out strengths of glass-ionomer cement and 4-META adhesive resin.

Acid Etching, Dental↗

[The effect of trematode invasion and chromium sulphate on the crude protein content in the haemolymph of Viviparus viviparus (Mollusca: Gastropoda: Pectinibranchia)].

The combined effect of the trematode infection (Echinoparyphium sp.) and various concentrations of chromium sulphate (0.01, 1, 100 mg/l) onto the crude protein content in the haemolymph of the mollusc Viviparus viviparus was investigated. The normal contents of the crude protein is 0.7-1.22%. In adult specimens its concentration is 20-80% higher than in molluscs of junior age group. Sex difference by this index, which is higher in females, begins to manifest in four year old individuals only. The contents of crude protein in the haemolymph of pregnant females is 1.5 times higher than in latent ones. Under the low intensity of the trematode infection, the contents of crude protein in the haemolymph remains normal, while in the case of heavy infection, it decrease 100 times or lower. In the cases of 0.01-1 mg/l concentrations of chromium sulphate, the content of protein in the haemolymph of V. viviparus decreases, while in the case of 100 mg/l it increases abruptly, in comparison to the norm. The trematode infection intensifies these processes.

Animals↗

[Determination of chromium(III) and chromium(VI) in water using flow injection on-line preconcentration and separation with flame absorption spectrometric detection].

A rapid and sensitive method for the sequential determination of Cr(III) and Cr(VI) in water samples based on flow injection on-line preconcentration and separation with two-microcolumn system-flame atomic absorption spectrometry has been developed. The Cr(III) and Cr(VI) in water samples were respectively retained in a microcolum with cation exchange resin and in a microcolumn with anion exchange resin and were eluted directly by 15% HNO3 and 8% NH4NO3, respectively. The characteristic concentrations (pre-concentration time of 1 min) for Cr(III) and Cr(VI) were 1.50 micrograms.L-1 and 1.39 micrograms.L-1, respectively, The relative standard deviations at 10 micrograms.L-1 level were 3.41% and 1.80%, and the corresponding detection limits (3 sigma) were 1.03 micrograms.L-1 and 0.54 microgram.L-1, respectively. The satisfactory recovery of 93.48%-107.5% could be obtained from water samples.

Chromium↗