SEARCH · Search PubMed

Results for “Hydroxides”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26Linked to original sources

PubMed2000

Immobilization with metal hydroxides as a means to concentrate food-borne bacteria for detection by cultural and molecular methods.

The application of nucleic acid amplification methods to the detection of food-borne pathogens could be facilitated by concentrating the organisms from the food matrix before detection. This study evaluated the utility of metal hydroxide immobilization for the concentration of bacterial cells from dairy foods prior to detection by cultural and molecular methods. Using reconstituted nonfat dry milk (NFDM) as a model, two food-borne pathogens (Listeria monocytogenes and Salmonella enterica serovar Enteritidis) were concentrated from 25-ml samples by the sequential steps of clarification and high-speed centrifugation (designated primary concentration) and immobilization with zirconium hydroxide and low-speed centrifugation (designated secondary concentration). Sample volume reduction after immobilization with zirconium hydroxide was 50-fold, with total bacterial recoveries ranging from 78 to 96% of input for serovar Enteritidis and 65 to 96% of input for L. monocytogenes. Immobilized bacteria remained viable and could be enumerated by standard cultural procedures. When followed by RNA extraction and subsequent detection by reverse transcription (RT)-PCR, detection limits of 10(1) to 10(2) CFU/25 ml of reconstituted NFDM were achieved for both organisms. The bacterial-immobilization step was relatively nonspecific, resulting in recovery of >50% of the input cells when evaluated on a panel of representative bacterial strains of significance to foods. The method could be adapted to more complex dairy products, such as whole milk and ice cream, for which bacterial recoveries after immobilization ranged from 64 to >100%, with subsequent RT-PCR detection limits of >/=10(2) CFU/ml for whole milk and >/=10(1) CFU for ice cream for both serovar Enteritidis and L. monocytogenes. The bacterial-immobilization method is easy, rapid, and inexpensive and may have applications for the concentration of a wide variety of food-borne bacteria prior to detection by both conventional and alternative methods.

Animals↗

PubMedDate not supplied

Toxic effects of chromium acetate hydroxide on cells cultivated in vitro.

Many human activities, particularly industrial ones, result in an ever-growing production of toxic waste materials. The dynamics of the toxic effects of chromium acetate hydroxide, which is found in high concentrations in a waste sediment produced in the Czech Republic, were assessed by using a battery of in vitro tests carried out on two cell lines: L-929 (mouse fibroblasts) and Hep 2 (human laryngeal cells). Various markers of cell damage were assessed by phase-contrast, video and fluorescence microscopy, fluorometry, and DNA analysis. Chromium acetate hydroxide, over a concentration range of 1-0.02mol/l induced immediate cell death by fixation, whereas, at 0.002mol/l, the treated cells died in a much slower, more discrete manner. All the detected markers of cell damage, whether immediate or slow, clearly demonstrated that the cells died by necrosis. On the other hand, test concentration of 0.001mol/l appeared to constitute a threshold at which no pathological changes of Hep 2 cells were observed over 96 hours. We conclude that chromium acetate hydroxide has a high toxic potential in vitro, which should be considered when studying the toxicity of waste materials containing it.

Animals↗

PubMed2002

Magnetized carbonyl iron and insoluble zirconium hydroxide mixture facilitates bacterial concentration and separation from nonfat dry milk.

A mixture of magnetized carbonyl iron and insoluble zirconium hydroxide was investigated for its ability to concentrate various foodborne pathogens from 25-ml samples of reconstituted nonfat dry milk. Each sample was artificially contaminated with 10(3) to 10(6) CFU/25 ml of representative foodborne pathogens (Salmonella enterica serovar Enteritidis, Listeria monocytogenes, and Bacillus cereus spores) and processed for bacterial concentration with high-speed centrifugation for the primary concentration followed by a secondary concentration step involving the carbonyl iron-zirconium hydroxide mixture. Bacterial recoveries, as evaluated on the basis of loss to discarded supernatants, exceeded 75% for all organisms at all inoculum levels and were usually >90%. Recovery was confirmed by direct plating of the immobilized pellet, for which the valueswere similar albeit more varied. Additional experiments confirmed that the magnetized carbonyl iron-insoluble zirconium hydroxide mixture was relatively nontoxic to both Salmonella Enteritidis and L monocytogenes Overall, the entire concentration scheme resulted in a 25-fold reduction in sample volume with the recovery of viable bacterial cells. This novel compound shows promise for facilitating inexpensive, rapid, and effective bacterial concentration in food systems.

Animals↗

PubMed1984

Iron pharmacokinetics after administration of ferric-hydroxide-polymaltose complex in rats.

This paper reports a study of the pharmacokinetics of ferrous sulphate and ferric-hydroxide-polymaltose complex (Hw 6400, Ferrum Hausmann) administered orally and intravenously to anaemic and non-anaemic rats of both sexes. Radiolabelled ferrous sulphate and ferric-hydroxide-polymaltose complex was used to study iron utilization after oral administration. Measurements of radioactivity in serum, packed red cells, whole blood, liver, kidney, spleen, bone and in some cases in the gastrointestinal tract were made following a range of dosages between 0.84 and 41.9 mg Fe/kg. No significant difference in bioavailability or iron utilization was found between the two iron preparations. Pharmacokinetic measurements following i.v. administration showed different distribution volumes, iron clearance and elimination constants for the two preparations. This difference in pharmacokinetic behaviour following oral administration, particularly in the case of non-anaemic rats, was confirmed by the observation that a 10- to 20 fold smaller dose of FeSO4 than of iron-polymaltose complex was required to achieve the same rise in serum iron. It is therefore not justifiable to draw conclusions about the bioavailability of chemically different iron preparations (iron salts and iron hydroxide complexes) on the basis of AUC values for serum iron increases observed in non-anaemic animals or human subjects.

Administration, Oral↗

PubMed1996

Pharmacokinetics of iron(III)-hydroxide sucrose complex after a single intravenous dose in healthy volunteers.

The pharmacokinetics of iron were investigated after intravenous administration to 12 healthy volunteers of iron(III)-hydroxide sucrose complex (Venofer) as a single i.v. dose containing 100 mg Fe. The average predose concentration was 35.7 +/- 12.5 mumol/l. There was no statistically significant difference between the serum iron level before injection (0 h) and the level at 24 h after the injection. The compartment model used includes a Michaelis-Menten term and is in excellent agreement with the observed exchange of iron to transferrin and with the daily iron turnover by transferrin. The intravenously injected iron(III)-hydroxide sucrose complex led rapidly to high serum iron levels. Maximum measured levels averaged 538 mumol/l (30.0 mg/l) at 10 min after the injection. The terminal half-life of the injected iron was calculated to be 5.3 h. Mean total area under the curve (AUC) was 1491 mumol/l h, the mean residence time (MRT) was 5.5 h. The total body clearance was 20.5 ml/min. The volume of distribution of the central compartment (Vc) was 3.21, hence close to the volume of the serum; the volume of distribution at steady state (Vdss) was 7.31; and the volume of distribution during elimination (Vdarea) was 9.21. The calculated amount of iron transported by transferrin was 31.0 +/- 6.6 mg Fe/ 24h. In summary, the data show that the injected iron(III)-hydroxide sucrose complex is quickly cleared from the serum with a terminal half-life of approximately 5-6 h. Renal elimination of iron contributed very little to the overall elimination (in average < 5%). Renal elimination of sucrose averaged about 68 +/- 10% and 75 +/- 11% of the administered dose after 4 h and 24 h, respectively.

Adult↗

PubMed1979

Methylmercury hydroxide enhancement of translation and transcription of ovalbumin and conalbumin mRNA's.

Translation of total mRNA in heterologous protein-synthesizing systems is often employed as an indirect means of assessing relative mRNA concentrations. However, it is well known that the efficiency of translation of specific mRNAs differs. One such example is the poor translational efficiency of conalbumin mRNA relative to ovalbumin mRNA. In this report we have studied the translation of conalbumin and ovalbumin mRNAs in crude mRNA preparations and with highly purified mRNA preparations. We find that treatment of RNA with methylmercury hydroxide prior to translation improves the translational efficiency of both mRNAs and preferentially improves translational efficiency of conalbumin mRNA to the point where it more correctly reflects the relative concentration of these two mRNAs in crude mRNA preparations. Conalbumin mRNA is also a poor template for the synthesis of full length cDNA synthesis by avian myeloblastosis virus reverse transcriptase, and treatment of this mRNA with methylmercury hydroxide increases the size of DNA sequences synthesized. We conclude that treatment with methylmercury hydroxide produces a partial denaturation of mRNA complexed with either itself or with other RNA molecules and results in more efficient utilization in both translational assays and DNA polymerization reactions.

Animals↗

PubMed2004

Intercalation of amino acids and peptides into Mg-Al layered double hydroxide by reconstruction method.

The intercalation of amino acids and some peptides into Mg-Al layered double hydroxide known as hydrotalcite was examined. Although the intercalation by ion-exchange method was unsuccessful, all the amino acids except for Lys and Arg, and peptides examined could be intercalated into the layered double hydroxide by reconstruction method using Mg-Al oxide precursor. The uptake amounts of amino acids and peptides were 0.9-2.7 mmol per 1 g of LDH. Intercalation compounds were examined by using XRD and solid-state NMR. For Gly, Ala, Ser, Thr, Pro, Asn, Gln, Asp, Glu, and aspartame the intercalation accompanied the expansion of interlayer distance of the solid products, whereas the other amino acids and oligoglycine showed no expansion. The intercalation mechanism and release profile in K(2)CO(3) aqueous solution were also investigated. And the cointercalation of amino acids and peptides into Mg-Al LDH and easy release of amino acids from the LDH layer were found.

Aluminum Hydroxide↗

PubMed2005

First insight into catalytic activity of anionic iron porphyrins immobilized on exfoliated layered double hydroxides.

Mg-Al layered double hydroxide (LDH) intercalated with glycinate anions was synthesized through co-precipitation and exfoliated in formamide and the single-layer suspension was reacted with aqueous iron porphyrin solutions (Fe(TDFSPP) and Fe(TCFSPP)). The obtained materials were characterized by X-ray powder diffraction, UV-vis, and electron paramagnetic resonance and investigated in the oxidation reaction of cyclooctene and cyclohexane using iodosylbenzene as oxidant. The iron porphyrin seems to be immobilized at the surface of the glycinate intercalated LDH. The catalytic activities obtained in heterogeneous media for iron porphyrin, Fe(TDFSPP), was superior to the results obtained under homogeneous conditions, but the opposite effect was observed on the Fe(TCFSPP), indicating that, instead of the structural similarity of both iron porphyrins (second-generation porphyrins), the immobilization of each one produced different catalysts. The best catalytic activity of the Fe(TDFSPP)/Gly-LDH, compared to Fe(TCFSPP)/Gly-LDH, can be explained by the easy access of the oxidant and the substrate to the catalytic sites in the former, probably located at the surface of the layered double hydroxide pillared with glycinate anions. A model for the immobilization and a mechanism for the oxidation reaction will be discussed.

Aluminum Hydroxide↗

PubMed1986

Selective preconcentration of polynuclear aromatic hydrocarbons and polychlorinated biphenyls by in situ metal hydroxide precipitation.

An investigation of selective concentration of analytes from aqueous samples by in situ magnesium hydroxide precipitation, as described by Faltusz, has yielded the following results: the method is selective for polycyclic aromatic hydrocarbons and polychlorinated biphenyls of higher molecular weight: it discriminates strongly against acidic molecules, and other neutral and basic molecules are only partially recovered; a variety of metal hydroxides could evidently be used in this method, but magnesium appears to have practical advantages over some of the others; the reproducibility of analyses on pure water samples is acceptable (ca.20% relative standard deviation), but the results from natural samples show lower recovery and wider variability; a preliminary test, in which this method was used to discriminate against major amounts of interfering solutes, shows promise that this technique might have unique advantages in certain situations.

Chemical Phenomena↗

PubMed2002

Ion chromatographic analysis of anions in ammonium hydroxide, hydrofluoric acid, and slurries, used in semiconductor processing.

In this study, ion chromatography (IC) with suppressed conductivity detection was used for the determination of trace anions in 29% (w/w) ammonium hydroxide, 49% (w/w) hydrofluoric acid and slurries. For these samples, various sample pretreatment methods were applied to eliminate matrix interferences. For concentrated ammonium hydroxide, an on-line electrochemical neutralizer (SP10 AutoNeutralization module) was used to neutralize the base prior to the IC analysis. For concentrated hydrofluoric acid, a heart cutting technique with an ion-exclusion column was used to separate the anions of interest prior to an IC separation. A method was also developed to analyze chloride in silica slurries by IC.

Ammonium Hydroxide↗

PubMed2001

Kinetics of phthalate reactions with ammonium hydroxide in aqueous matrix.

Common phthalate pollutants, such as dimethyl phthalate and diethyl phthalate found in aqueous environmental matrices react with ammonium hydroxide at ordinary temperatures exhibiting an overall reaction order in the range 1.3-1.4. While the reaction is of first order with respect to the phthalate, the order of reaction is fractional in ammonium hydroxide. The rate constants for the reactions of these two phthalates in alkaline waters at ambient temperatures are in the range 1.3 x 10(-4) and 8.5 x 10(-5) Lx/mol s. Under these conditions the estimated half-lives for dimethyl phthalate and diethyl phthalate at a concentration of each at 20 mg/L is 4.5 and 14 h, respectively. Other phthalates are expected to exhibit similar kinetics in their base hydrolysis with NH4OH. Thus, the presence of both the phthalate esters and ammonia or ammonium salts in the water under alkaline conditions may result in their self-removal by hydrolysis.

Ammonium Hydroxide↗

PubMed1997

Recovery of nucleic acids from immobilized biotin-streptavidin complexes using ammonium hydroxide and applications in MALDI-TOF mass spectrometry.

The effects of ammonium hydroxide treatment of complexes consisting of biotinylated nucleic acids and immobilized streptavidin were investigated. It was found that incubation of such complexes with ammonium hydroxide at room temperature leads to denaturation of double-stranded DNA molecules, liberating only the complementary nonbiotinylated strand, whereas incubation at elevated temperatures leads to an efficient dissociation of biotin-streptavidin complexes. The introduced procedure is especially suitable as a purification and conditioning format prior to matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometric analysis of DNA from complex enzymatic reactions. This is demonstrated by analysis of polymerase chain reaction (PCR) and sequencing products.

Ammonium Hydroxide↗

PubMed2006

Dispersion and size control of layered double hydroxide nanoparticles in aqueous solutions.

We report a simple but efficient method to prepare stable homogeneous suspensions containing monodispersed MgAl layered double hydroxide (LDH) nanoparticles that have wide promising applications in cellular drug (gene) delivery, polymer/LDH nanocomposites, and LDH thin films for catalysis, gas separation, sensing, and electrochemical materials. This new method involves a fast coprecipitation followed by controlled hydrothermal treatment under different conditions and produces stable homogeneous LDH suspensions under variable hydrothermal treatment conditions. Moreover, the relationship between the LDH particle size and the hydrothermal treatment conditions (time, temperature, and concentration) has been systematically investigated, which indicates that the LDH particle size can be precisely controlled between 40 and 300 nm by adjusting these conditions. The reproducibility of making the identical suspensions under identical conditions has been confirmed with a number of experiments. The dispersion of agglomerated LDH aggregates into individual LDH crystallites during the hydrothermal treatment has been further discussed. This method has also been successfully applied to preparing stable homogeneous LDH suspensions containing various other metal ions such as Ni(2+), Fe(2+), Fe(3+), Co(2+), Cd(2+), and Gd(3+) in the hydroxide layers and many inorganic anions such as Cl(-), CO(3)(2-), NO(3)(-), and SO(4)(2-).

Aluminum Hydroxide↗

PubMed2002

Loss of hydroxyl ions from gutta-percha points with calcium hydroxide in their composition: an in vivo study.

The aim of this study was to quantify variations in the pH of calcium-hydroxide, gutta-percha cones that had remained for 1 week inside the root canals of molars or premolars whose endodontic treatment could not be concluded in a single visit. All teeth were instrumented and dried before the placement of the points. The cones were removed, and placed in vials with distilled water. Additional, new gutta-percha cones were also studied as a control. The pH was measured by a pH meter, model CRISON MicropH 2001. The average pH mensurations obtained for new, calcium-hydroxide, gutta-percha points was 10.11; for cones that were used 1 week, it was 7.08. There was a statistically significant difference observed between the two groups by the Student's t test (p > 0.001). After 7 days, a significant decrease takes place in the alkalinity of these points.

Alkalies↗

PubMed1986

The effect of sodium bicarbonate versus aluminum-magnesium hydroxide on postprandial gastric acid in duodenal ulcer patients.

When ingested 1 hour after a meal, conventional liquid antacids have a buffering effect of approximately 2 hours, while in the fasting state their effect is brief, lasting less than 1 hour. We tested the hypothesis that equal doses of antacid, one water soluble (sodium bicarbonate) and the other water insoluble (aluminum hydroxide plus magnesium hydroxide, MaaloxR), would have similar durations of postprandial buffering if the water soluble antacid regenerates the particulate protein buffer of the meal that leaves the stomach more slowly than liquids. Tests were conducted in random order on three separate days in 10 patients with duodenal ulcer. The effects of 30 ml of 2.39 M sodium bicarbonate (6.17 g, about 1 teaspoonful), the aluminum-magnesium antacid, each equivalent to 71.7 mmol of in vitro buffer, and water as a control on pH, hydrogen ion activity, and titratable acidity were compared. Thirty milliliters of each was swallowed 1 and 3 hours after ingestion of a standard solid plus liquid. Compared to the water control each dose of sodium bicarbonate significantly increased intragastric pH and decreased hydrogen ion activity and titratable acidity for only 1 hour. Each dose of the aluminum-magnesium antacid significantly buffered intragastric contents for 2 hours. These findings indicate that sodium bicarbonate transiently buffers postprandial intragastric contents. Therefore, sodium bicarbonate fails to reconstitute the protein buffer of the meal effectively, and the observations suggest that it leaves the stomach rapidly with the liquid phase of the meal. However, the water insoluble, aluminum-magnesium antacid has a longer duration of buffering, probably because it leaves the stomach more slowly, largely with the solid portion of the meal.

Adult↗

PubMed1992

The effects of famotidine, ranitidine and magnesium hydroxide/aluminium hydroxide on gastric fluid pH in adult horses.

Gastric fluid pH was measured in five adult horses following nasogastric administration of famotidine, 0.5, 1.0, and 2.0 mg/kg bodyweight (bwt); ranitidine, 4.4 and 6.6 mg/kg bwt and an antacid containing magnesium hydroxide (40 mg/ml) and aluminium hydroxide (45 mg/ml), 120 and 180 ml. Fluid was aspirated through a 16 French nasogastric feeding tube at 15 min intervals, and pH was measured using a pH meter. Basal gastric fluid pH was measured at 20 min intervals for 6 h in each horse and, with the exception of two measurements of 4.66 and 4.17, ranged from 1.42 to 2.41, with a mean pH of 1.88 +/- 0.18. The response to both ranitidine and famotidine was variable between horses and between dosages. The mean gastric fluid pH values following administration of a single dose of famotidine or ranitidine were famotidine, 0.5 mg/kg bwt, 3.63 +/- 1.72; famotidine, 1.0 mg/kg bwt, 3.41 +/- 1.40; famotidine, 2.0 mg/kg bwt, 4.18 +/- 2.06; ranitidine, 4.4 mg/kg bwt, 4.07 +/- 1.25; ranitidine 6.6 mg/kg bwt, 5.34 +/- 1.12. Differences in mean gastric fluid pH between famotidine dose levels and between ranitidine dose levels were not significant (P > 0.10). Gastric fluid pH increased to greater than 6 in three horses receiving 0.5 mg/kg bwt, five horses receiving 1.0 mg/kg bwt and three horses receiving 2.0 mg/kg bwt famotidine. Gastric fluid pH increased to greater than 6 in each of the five horses receiving 6.6 mg/kg bwt ranitidine and in four of five horses receiving 4.4 mg/kg bwt ranitidine. During the 6 h post administration, ranitidine tended to increase gastric fluid pH greater than 6 longer (166 +/- 106 mins) than famotidine (98 +/- 110 mins) and this difference was nearly significant (P = 0.054). The response to antacid was variable and consistently short-lived. The mean gastric fluid pH values for 6 h after administration of 120 ml or 180 ml were 2.42 +/- 0.71 and 2.44 +/- 0.47, respectively. Gastric fluid pH increased to greater than 6 in only two horses, for 15 and 30 mins, respectively. The increase in gastric fluid pH was significantly greater for ranitidine (P < 0.001) and famotidine (P < 0.02) than for antacid. The duration of the effect was significantly longer for ranitidine doses (P < 0.001) and nearly so for famotidine doses (P < 0.055) than for antacid.

Aluminum Hydroxide↗

PubMed1993

Effects of magnesium-aluminum hydroxide antacid on absorption of rufloxacin.

The present study was designed to determine the effects of an antacid suspension containing magnesium hydroxide and aluminum hydroxide (30 ml of Maalox) on the oral bioavailability of rufloxacin (400 mg). Rufloxacin was administered orally to 12 healthy volunteers according to a randomized, balanced, crossover design. Three treatments were administered to each subject, with a 10-day washout period between treatments; the treatments included rufloxacin alone, rufloxacin taken 5 min after antacid, and rufloxacin taken 4 h before antacid. Administration of antacid within 5 min before the administration of rufloxacin resulted in a substantial decrease in rufloxacin absorption, with a mean percent relative bioavailability compared with control values of 64% (range, 42 to 77%). Administration of antacid 4 h after the administration of rufloxacin slightly affected the absorption of the quinolone (mean relative bioavailability, 87%; range, 51 to 110%). Antacids that contain magnesium and aluminum salts reduce the absorption of rufloxacin. The extent of this interaction depends on the time that elapses between administration of the two drugs.

Administration, Oral↗

PubMed1995

Ethylenediaminetetraacetic acid in ammonium hydroxide for reducing decalcification time.

Ethylenediaminetetraacetic acid (EDTA) solution is used to decalcify bone specimens for histological examination. Sodium hydroxide (NaOH) has been used to dissolve EDTA and to bring EDTA solutions to neutral pH. This solution, however, requires several weeks to decalcify bone specimens. We investigated a new decalcification fluid using concentrated ammonium hydroxide (NH4OH) to dissolve EDTA and to adjust the pH to neutral. Decalcification was performed using a magnetic stirrer with and without vacuum, or with a sonic cleaner. Decalcification end point was confirmed using both the weight loss and X-ray methods. After decalcification, specimens were processed through paraffin and sections were stained with hematoxylin and eosin. Decalcification employing NH4OH required an average of six days. Light microscopy indicated good retention of cellular detail.

Ammonium Hydroxide↗