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PubMed1991

Erosion process of calcium hydroxide cements in water.

Erosion process of calcium hydroxide cements was examined for 7 days by chemical analysis of eluates and observation of structural change of the eroded cements when the cements were immersed in water at 37 degrees C. The elution of salicylate from the set cements as well as that of Ca continued during the immersion time. In the early stage of the erosion, unreacted Ca(OH)2 was preferentially extracted from the cements in comparison with Ca-alkyl salicylate chelate of the cement matrix. The elution rate of N-ethyl o- and p-toluene sulphonamides, which were contained as plasticizer, was higher than those of Ca and salicylate. Insoluble inorganic filler remained at the surface of the cements after extraction of unreacted Ca(OH)2 and disintegration of the cement matrix. Types of salicylate ester seemed to affect the cement durability.

Calcium Hydroxide↗
PubMed1992

Stability constants of Ca-alkyl salicylate complexes and their effect on the dissolution of calcium hydroxide dental cements.

The proton-ligand stability constants (pKa) and Ca-ligand stability constants (log beta) of the five types of alkyl salicylate were determined and the dissolution of the calcium hydroxide cements prepared from those salicylates was examined in water. The dissolution of the cements containing monoesters decreased with the increase in their pKa and log beta values. The cement containing diester showed lower dissolution than that estimated from those values. This seems to be related to the polymeric structure of the cement matrix consisting of the complex of the diester with calcium.

Calcium Hydroxide↗
PubMed1989

In vitro assessment of viral antigen content in inactivated aluminum hydroxide adjuvanted vaccines.

Antigen capture enzyme immunoassays (ELISA) were developed to assess the antigenic content of inactivated aluminum hydroxide (AH) adjuvanted porcine parvovirus, pseudorabies, and infectious bovine rhinotracheitis vaccines. Reference preparations of these viruses were constructed as a basis for comparison. Because AH-associated ELISA interference was largely circumvented, the need for isotopic or complex antigen-adjuvant desorption methods was eliminated. A 4-parameter logistic model related optical density to vaccine dilution. High correlation coefficients (r) were routinely achieved with commercial monovalent and polyvalent vaccines, and reference preparations. The procedure quantified antigen in both aqueous and AH-associated phases. The method may be generally applicable as a partial substitute for in vivo vaccine potency testing by allowing in vitro estimation of inactivated viral antigenic content in AH adjuvanted vaccines.

Adjuvants, Immunologic↗
PubMed1993

A comparative study of the immune responses of sheep against foot-and-mouth disease virus types Asia-1 and O PEG-concentrated aluminium hydroxide gel and oil-adjuvanted vaccines.

Foot-and-mouth disease (FMD) vaccines prepared against types Asia-1 and O PEG-concentrated and adjuvanted with aluminium hydroxide gel were compared with oil-adjuvanted types Asia-1 and O vaccines in sheep. The study was conducted by inoculating 0.5 ml of monovalent vaccine under laboratory conditions and 1 ml dose of bivalent vaccine in field conditions. The antibody responses were monitored by serum neutralization and ELISA tests. The results indicate that PEG-concentrated gel vaccine was of comparable immunogenicity to oil-adjuvanted vaccine over a study period of 8 weeks. No significant difference was observed in the antibody response with monovalent or bivalent vaccine. However, to substantiate the present findings and reach a final conclusion, further studies with both vaccines may have to be carried out over a longer period of time.

Adjuvants, Immunologic↗
PubMed1993

Studies on the toxicities of aluminium hydroxide and calcium phosphate as immunological adjuvants for vaccines.

Aluminium hydroxide (Al) and calcium phosphate (Ca) have been used for many years as immunological adjuvants for biologicals. We investigated the toxic effects of both adjuvants with different physical properties. Al-gel elicited vascular permeability-increasing and toxic effects to macrophages (M phi), while its haemolytic effect was weak. Ca-gel elicited a significantly stronger haemolytic effect, but no other toxic effect. Incubation of M phi or polymorphonuclear leucocytes with Al-suspension resulted in the largest release of lactate dehydrogenase. Ca-suspension caused haemolysis of about 50% of that caused by Ca-gel.

Adjuvants, Immunologic↗
PubMed1995

A single administration of tetanus toxoid in biodegradable microspheres elicits T cell and antibody responses similar or superior to those obtained with aluminum hydroxide.

The use of biodegradable polymer microspheres as a single dose vaccine delivery system was investigated by using tetanus toxoid (TT). In order to compare the immunogenicity of TT-microspheres (TT-MS) with aluminum hydroxide (alum)-based TT, BALB/c mice were immunized with TT in different formulations including individual or mixtures of MS and TT-alum. All TT-MS formulations elicited high proliferative and antibody responses comparable to those obtained with TT-alum formulation. Antibody levels remained elevated over a long period of time. Certain individual MS preparations elicited lower antibody titers than the MS mixtures. More importantly, the proliferative and antibody responses induced by a single injection of three TT-MS mixtures with different particle sizes and degradation rates were similar to those obtained with three injections of TT-alum. In addition, TT-MS induce similar isotypesubclass antibodies to those TT-alum induced. These results raise the possibility to obtain optimal and long-lasting immune responses by single administration of the three TT-MS mixture formulations alone.

Aluminum Hydroxide↗
PubMed1994

Impact of the saponin adjuvant QS-21 and aluminium hydroxide on the immunogenicity of recombinant OspA and OspB of Borrelia burgdorferi.

The impact of the adjuvants QS-21 and aluminium hydroxide (alum) on the immunogenicity of recombinant outer surface proteins A (OspA) and B (OspB) of Borrelia burgdorferi was investigated. Both non-acylated OspA and OspB derived from strain B31 were expressed in Escherichia coli and purified by reversible citraconylation and anion-exchange chromatography. Antisera to OspA or OspB were prepared in mice with antigens formulated with QS-21 or alum, and evaluated for specific immunoglobulin G isotypes, agglutination and borreliacidal activity. QS-21 significantly enhanced IgG2a and IgG2b antibody responses to OspA and OspB, and IgG1 response to OspA when compared with the formulation containing antigen alone. In contrast, alum significantly inhibited the induction of IgG2a and IgG2b responses to OspA. Alum had no significant effect on IgG1 response to OspA, or IgG2a and IgG2b responses to OspB, but significantly enhanced IgG1 antibody response to OspB. Antisera to OspA or OspB formulated by QS-21 possessed higher titres of agglutinating antibody than antisera to OspA or OspB alone. Borreliacidal activity was eight- to 64-fold higher in antisera to OspA formulated with QS-21 than in antisera to OspA formulated with or without alum. These antisera were highly borreliacidal to New York strain B31, a California isolate CA-2-87, German isolate Fr, and Swedish isolate G25. Antisera to OspB formulated with QS-21 were highly borreliacidal to strains B31 and Fr, but not to CA-2-87 and G25. Antisera to OspB formulated with alum were borreliacidal only to B31. Thus, OspA was superior to OspB and QS-21 superior to alum at eliciting functional antibody responses.(ABSTRACT TRUNCATED AT 250 WORDS)

Adjuvants, Immunologic↗
PubMed1994

Relationship between protein adsorptive capacity and the X-ray diffraction pattern of aluminium hydroxide adjuvants.

Thermal treatment during the preparation of aluminium hydroxide adjuvants affects the primary crystallite size of the adjuvant. The primary crystallite size can be characterized by the line broadening of the (020) reflection of the X-ray diffraction pattern. Studies of protein adsorption using bovine serum albumin as a model protein revealed a direct relationship between the albumin adsorptive capacity and the width at half height (WHH) of the (020) reflection in the X-ray diffraction pattern.

Adjuvants, Immunologic↗
PubMed1988

Decrease of serum triglyceride in normal rat fed with 2000 ppm aluminum diet for 67 days. II. Feeding young and adult rats a sucrose diet with addition of aluminum hydroxide and aluminum potassium sulfate.

To confirm the hypotriglyceridemic effect of aluminum (Al), male weanling and adult Wistar rats were fed sucrose diets with the addition of aluminum hydroxide (Al(OH)3) or aluminum potassium sulfate (AlK(SO4)2) for 67 days. As in the foregoing report (C. Sugawara, N. Sugawara, H. Kiyosawa, and H. Miyake, Fundam. Appl. Toxicol. 10, 607-615), no Al-induced anemia or hypophosphatemia was observed and serum Al did not exceed 20 ng/ml. Serum triglyceride (TG) was decreased by aluminum. Serum TG was significantly correlated with the serum nonesterified fatty acid (NEFA) concentration in both the Young groups (R = 0.757, n = 22, p less than 0.01) and the Adult groups (R = 0.727, n = 19, p less than 0.01). Neither serum cholesterol nor phospholipids was affected by Al ingestion. Aluminum caused a decrease in hepatic glycogen in all groups, but the decrease was significant only in Adult groups. Glycerol tri[9,10(n)-3H]oleate was administered by gastric tube into rats fed for 81 days with experimental diets. In all the Al-treated groups serum 3H was significantly greater than in control groups at 3 hr after intubation. At 24 hr after intubation, serum 3H did not differ between Control and Al-treated groups. Total 3H at 24 hr found in serum, liver, and epididymal adipose tissue was not changed significantly by Al feeding. These effects were observed without measurable increase of Al in the serum.(ABSTRACT TRUNCATED AT 250 WORDS)

Alum Compounds↗
PubMedDate not supplied

A comparison of calcofluor white, potassium hydroxide, and culture for the laboratory diagnosis of superficial fungal infection.

A total of 207 skin scrapings were prospectively studied using potassium hydroxide (KOH), calcofluor white (CW), and culture to determine the clinical usefulness of each microscopic method. For dermatophytes (prevalence 13.2%), CW had a sensitivity of 92% and a specificity 95%, giving a positive predictive value of 74% and negative predictive value of 99%. KOH had a sensitivity of 88% and a specificity of 95%, giving a positive predictive value of 73% and a negative predictive value of 98%. CW was simple, rapid, and easy to read. For dermatophyte infection, CW results are as useful as KOH results.

Arthrodermataceae↗
PubMed2006

The effect of calcium hydroxide on solubilisation of bio-active dentine matrix components.

Calcium hydroxide (Ca(OH)(2)) has been used extensively to induce dentine regeneration through formation of dentine bridges at sites of pulp exposure after dental tissue injury, however, the biological processes underpinning these events are unclear. We hypothesise that growth factors and other bio-active molecules, sequestered within dentine matrix, may be released by the action of Ca(OH)(2) and signal gene expression in pulp cells, which mediates the changes in cell behaviour observed during regeneration. Powdered sound, human dentine samples were extracted with either 0.02 m Ca(OH)(2), pH 11.7 or 10% EDTA, pH 7.2 ( a control known extractant of bio-active and other ECM molecules from dentine) over a 14-day period. Extracts were compared for non-collagenous protein (NCP) and glycosaminoglycan (GAG) content using dye binding assays and protein compositions were analysed by 1D-polyacrylamide gel electrophoresis (1D-PAGE) and TGF-beta1 ELISA. The effects of extracts on TGF-beta1, Collagen-1alpha and Nestin gene expression were analysed using semi-quantitative RT-PCR in the dental MDPC-23, OD-21 and fibroblastic Swiss 3T3 cell lines following 24h of exposure. Ca(OH)(2) solubilised NCPs and GAGs from the dentine ECM, although with a lower yield than the EDTA solution and with different kinetics. 1D-PAGE analysis demonstrated some differences in profiles for proteins solubilised from dentine by Ca(OH)(2) and EDTA. Both solutions released TGF-beta1 from the dentine with higher concentrations present in the EDTA (1.395 +/- 0.036 ng/mg) versus the Ca(OH)(2) (0.364 +/- 0.012 ng/mg) extract. Notably, both extracts induced similar gene expression profiles in all cell lines. These data provide a rational explanation for the action of Ca(OH)(2) during pulp capping in which the cellular activities involved in dentine bridge formation may be mediated through release of growth factors and other bio-active molecules from the dentine by Ca(OH)(2).

Base Sequence↗
PubMed2006

Laccase immobilization in redox active layered double hydroxides: a reagentless amperometric biosensor.

This paper describes a new system for amperometric determination of dissolved oxygen and its application for the detection of anionic toxic substances, which are known as enzyme inhibitors. This biosensor is based on the co-immobilization of laccase from Trametes versicolor and a redox active layered double hydroxide [Zn-Cr-ABTS] on a glassy carbon electrode. The electrochemical transduction step corresponds to the electrocatalytic reduction of O2 at 0.2V by laccase as catalyst and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as mediator. Such device provides a fast and a sensitive response for dissolved oxygen determination between 6 x 10(-8) and 4 x 10(-6)M and very low detection limits for azide (5.5 nM), fluoride (6.9 nM) and cyanide (6.2 nM).

Biosensing Techniques↗
PubMed2005

FTIR analysis of cellulose treated with sodium hydroxide and carbon dioxide.

Cellulose samples treated with sodium hydroxide (NaOH) and carbon dioxide in dimethylacetamide (DMAc) were analyzed by FTIR spectroscopy. Absorbance of hydrogen-bonded OH stretching was considerably decreased by the treatment of NaOH and carbon dioxide. The relative absorbance ratio (A(4000-2995)/A(993)) represented the decrease of absorbance as a criterion of hydrogen-bond intensity (HBI). The absorbance of the band at 1430cm(-1) due to a crystalline absorption was also decreased by NaOH treatment. The absorbance ratio of the bands at 1430 and 987-893cm(-1) (A(1430)/A(900)), adopted as crystallinity index (CI), was closely related to the portion of cellulose I structure. With the help of FTIR equipped with an on-line evacuation apparatus, broad OH bending due to bound water could be eliminated. FTIR spectra of the carbon dioxide-treated cellulose samples at 1700-1525cm(-1) were divided into some bands including 1663, 1635, 1616, and 1593cm(-1). The broad OH bending due to bound water at 1641-1645cm(-1) was resolved to two bands at 1663 and 1635cm(-1). As a trace of DMAc, the band at 1616cm(-1) is disappeared by washing for the cellulose treated with carbon dioxide (Cell 1-C and Cell 2/60-C). The decrease of HBI, the easy removal of DMAc, and the band at 1593cm(-1) supported the introduction of new chemical structure in cellulose. The bands shown at 1593 and 1470cm(-1) was assigned as hydrogen-bonded carbonyl stretching and O-C-O stretching of the carbonate ion.

Carbon Dioxide↗
PubMed2006

Sequential soil washing techniques using hydrochloric acid and sodium hydroxide for remediating arsenic-contaminated soils in abandoned iron-ore mines.

Sequential washing techniques using single or dual agents [sodium hydroxide (NaOH) and hydrochloric acid (HCl) solutions] were applied to arsenic-contaminated soils in an abandoned iron-ore mine area. We investigated the best remediation strategies to maximize arsenic removal efficiency for both soils and arsenic-containing washing solution through conducting a series of batch experiments. Based on the results of a sequential extraction procedure, most arsenic prevails in Fe-As precipitates or coprecipitates, and iron exists mostly in the crystalline forms of iron oxide. Soil washing by use of a single agent was not effective in remediating arsenic-contaminated soils because arsenic extractions determined by the Korean standard test (KST) methods for washed soils were not lower than 6mg kg(-1) in all experimental conditions. The results of X-ray diffraction (XRD) indicated that iron-ore fines produced mobile colloids through coagulation and flocculation in water contacting the soils, containing dissolved arsenic and fine particles of ferric arsenate-coprecipitated silicate. The first washing step using 0.2M HCl was mostly effective in increasing the cationic hydrolysis of amorphous ferrihydrite, inducing high removal of arsenic. Thus, the removal step of arsenic-containing flocs can lower arsenic extractions (KST methods) of washed soils. Among several washing trials, alternative sequential washing using 0.2M HCl followed by 1M HCl (second step) and 1M NaOH solution (third step) showed reliable and lower values of arsenic extractions (KST methods) of washed soils. This washing method can satisfy the arsenic regulation of washed soil for reuse or safe disposal application. The kinetic data of washing tests revealed that dissolved arsenic was easily readsorbed into remaining soils at a low pH. This result might have occurred due to dominant species of positively charged crystalline iron oxides characterized through the sequential extraction procedure. However, alkaline extraction using NaOH was effective in removing arsenic readsorbed onto the surface of crystalline minerals. This is because of the ligand displacement reaction of hydroxyl ions with arsenic species and high pH conditions that can prevent readsorption of arsenic.

Arsenic↗
PubMed2004

Automatic generation of ultra-pure hydroxide eluent for carbohydrate analysis of environmental samples.

High-performance anion-exchange chromatography coupled with pulsed amperometric detection under alkaline conditions has significantly improved our understanding of the function of carbohydrates in cycling of terrestrial carbon. The use of NaOH as an eluent has many advantages for anion analysis, but NaOH solutions are also an excellent trap for atmospheric CO2 resulting in eluent carbonate ion contamination. To minimize the carbonate contamination, eluent generation technology has been marketed that produces ultra-pure hydroxide (OH) eluents on demand. Application of this technology significantly reduced the amounts of OH present in the waste stream and provided faster chromatographic runs with greater sensitivity and precision for determining the monosaccharide composition from environmental samples. Minimizing the salt concentration to < or = 50 mm from acid hydrolysis extractions injected (25 microl injection volume) on column improved reproducibility of analyte retention times and separations. Eluent generation technology eliminated inconsistent OH eluent preparation that is often due to carbonate contamination. The contamination increases retention time variability for monosaccharides released by hydrolysis of biological samples.

Carbohydrates↗
PubMed2006

Evaluation of 6 years use of sodium hydroxide solution to clear partially occluded central venous catheters.

BACKGROUND & AIMS: Central venous catheter occlusion is a frequently occurring complication during home parenteral nutrition (HPN). The aim of the study was to investigate the effectiveness of sodium hydroxide (NaOH) administration to clear an occluded central venous catheter especially in HPN. METHOD: Retrospective study to the use of NaOH in partially occluded central venous catheters. About 45 patients with HPN treated in the Academic Medical Center of the University of Amsterdam (AMC) were included in this study between January 1997 and April 2003. Excluded from the study were patients under the age of 18 at the start of HPN and/or patients who use parenteral nutrition for less than 3 months. Partial catheter occlusion was defined as a spontaneous flow less than 60 drops/min. RESULTS: In total, 130 occlusions were registered in 29 HPN patients. The other 16 HPN patients did not report any occlusion. The incidence of occlusions in fat containing total parenteral nutrition (TPN) was 1 occlusion in 167 feeding days. TPN without fat showed only one occlusion (incidence 1 in 7126 feeding days). The use of a lipid emulsion proved an important risk factor for catheter occlusion in this study (P<0.05, RR=43). Ninety-five central venous catheter occlusions were treated with NaOH 0.1M. The remaining occlusions were total or mechanical occlusions making NaOH treatment impossible. In 73 out of 95 partial occlusions treatment with NaOH was effective (P<0.05). Using NaOH extended the use of 32 catheters (range 7-1592 days, mean 328). Twenty-one out of 32 catheters could be used for more than 3 months after using NaOH (P<0.05). CONCLUSION: We conclude that perfusion of a partial occluded central venous catheter (defined as 25-60 drops/min) used for parenteral nutrition with 0.1N NaOH is safe and shows a significant long term improvement in catheter care, by preventing total occlusion and operative removal.

Adult↗
PubMed2004

Enteric-coated layered double hydroxides as a controlled release drug delivery system.

Layered double hydroxides (LDHs) or so-called anionic clays consist of cationic brucite-like layers and exchangeable interlayer anions. Because of their biocompatibility, these layered inorganic solids can be used as host materials to create drug-LDH host-guest supramolecular structures. Because of the basicity of LDHs however, LDHs as drug delivery system will be limited for use in the stomach where pH is 1.2. A core-shell material has been prepared therefore in this work. A non-steroidal anti-inflammatory drug, Fenbufen-intercalated LDHs as the core was coated with enteric polymers, Eudragit S 100 or Eudragit L 100 as a shell, giving a composite material which shows controlled release of the drug under in vitro conditions which model the passage of a material through the gastrointestinal tract.

Delayed-Action Preparations↗
PubMed2006

Intercalation of hydrophilic and hydrophobic antibiotics in layered double hydroxides.

Four pharmaceutically active molecules, each representing a different class of antibiotic, were intercalated in layered double hydroxides. Two of them, gramicidin and amphotericin B, are hydrophobic, surface active drugs that were incorporated in artificial membranes formed in the interlayer of the inorganic host. The other two, ampicillin and nalidixic acid, are water soluble, commonly used antibiotics that were directly intercalated by using simple ion exchange reactions. The synthetic nanohybrid materials were characterized by various methods, as X-ray diffraction, infrared spectroscopy and ultraviolet-visible spectroscopy that verified the successful intercalation of the antibiotics and provided information regarding the interlayer structure of the nanohybrids. The reversible interaction of the antibiotic molecules with the inorganic host leads to release of the active drugs under the appropriate conditions. The release studies showed that the synthetic nanohybrids can successfully serve as controlled release systems for different kinds of antibiotics.

Amphotericin B↗