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PubMed1987

Desorption of porcine parvovirus from aluminum hydroxide adjuvant with subsequent viral immunoassay or hemagglutination assay.

Cell culture fluids containing porcine parvovirus were adjuvanted with varying concentrations of aluminum hydroxide gel. Adsorption of virus and total protein to adjuvant was proportional to adjuvant concentration. Desorption of virus and protein from the adjuvant in substantial, reproducible quantities was achieved by washing adjuvanted preparations with 1.2 M potassium phosphate, followed by dialysis and concentration of wash fluids. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of unadjuvanted viral fluids, supernatants of adjuvanted mixtures, and desorptive washings of the corresponding adjuvant pellets revealed no qualitative differences in protein banding patterns. Desorbed virus was quantitated by a hemagglutination assay, or by an enzyme-linked immunoassay employing a monoclonal anti-porcine parvovirus antibody. Virus desorption and subsequent assays permitted in vitro estimation of virus content in adjuvanted porcine parvovirus preparations. This approach may be useful in estimating the antigen content of inactivated aluminum hydroxide adjuvanted veterinary vaccines and reducing the extent of required in vivo testing.

Adjuvants, Immunologic↗
PubMed1980

Effects of aluminium hydroxide on restraint-induced and restraint delay-induced gastric ulceration in rats.

Rats given aluminium hydroxide after cold-restraint stress but before the 'post-stress delay' period, ulcerated significantly less severely and less frequently than rats given the drug before cold-restraint stress or those given water at either time period. Both aluminium hydroxide treated groups exhibited less ulceration than non-drug groups. These data suggest profound parasympathetic and hence, gastric acid, involvement in restraint delay-induced ulceration in rats.

Aluminum Hydroxide↗
PubMed1976

Radiogenic free radicals in apatite: the influence of fluoride and hydroxide.

Fluor-hydroxyapatites of varying fluoride and hydroxide contents were irradiated by soft x-rays at -188 degrees C and examined by means of electron spin resonance spectroscopy. Variation in fluoride-hydroxide contents affected radical yield and resulted in the observation of two kinds of oxygen anion resonances: a doublet due to hydrogen hyperfine splitting and a singlet. At higher temperatures a spin transfer process became operative which enhanced the oxygen anion radical population. Increasing fluoride content was paralleled by decreasing g-values for the oxygen anion resonances, possibly attributable to increased delocalization of the unpaired spin.

Electron Spin Resonance Spectroscopy↗
PubMed1998

The sodium hydroxide erosion assay: a revision of the alkali resistance test.

Burckhardt proposed the alkali resistance method as a means of assessing the integrity of the stratum corneum barrier in 1947. Researchers after Burckhardt largely found the test unreliable and nonreproducible; it therefore fell into disuse worldwide. We have upgraded the procedure by exposing the skin to 1.0 M sodium hydroxide under strictly specified conditions for successive 1-min periods until the emergence of the first erosions, revealed by staining with nitrazine yellow. Histology showed that the erosions were follicular and limited to the epidermis. The test was highly reproducible and repeatable. We demonstrated the usefulness of the test in the following ways: (1) the erosion time increased with aging, correlating with a thickened horny layer; (2) as few as five Scotch tape strippings greatly decreased the erosion time, although transepidermal water loss was only slightly increased; (3) slight damage to the horny layer by a 24-h exposure to 0.01% sodium lauryl sulfate sharply reduced the erosion time; (4) the erosion time decreased after daily open applications for 3 weeks of clobetasol propionate, corresponding to the thinned horny layer; (5) daily applications of petrolatum increased the erosion time. This new version of the alkali resistance test, renamed the sodium hydroxide erosion assay, promises to be a useful tool for studying the horny layer barrier in healthy and diseased skin.

Administration, Topical↗
PubMed2006

Salt effects on an ion-molecule reaction--hydroxide-catalyzed hydrolysis of benzocaine.

PURPOSE: This work investigates the effect of various salts on the rate of a reaction involving a neutral species (benzocaine alkaline hydrolysis). METHODS: Benzocaine hydrolysis kinetics in NaOH solutions in the presence of different salts were studied at 25 degrees C. Benzocaine solubility in salt solutions was also determined. Solubility data were used to estimate salt effects on benzocaine activity coefficients, and pH was used to estimate salt effects on hydroxide activity coefficients. RESULTS: Salts either increased or decreased benzocaine solubility. For example, solubility increased with 1.0 M tetraethylammonium chloride (TEAC) approximately 3-fold, whereas solubility decreased approximately 35% with 0.33 M Na2SO4. Salt effects on hydrolysis rates were more complex and depended on the relative magnitudes of the salt effects on the activity coefficients of benzocaine, hydroxide ion, and the transition state. As a result, some salts increased the hydrolysis rate constant, whereas others decreased it. For example, the pseudo-first-order rate constant decreased approximately 45% (to 0.0584 h(-1)) with 1 M TEAC, whereas it increased approximately 8% (to 0.116 h(-1)) with 0.33 M Na2SO4. CONCLUSIONS: Different salt effects on degradation kinetics can be demonstrated for a neutral compound reacting with an ion. These salt effects depend on varying effects on activity coefficients of reacting and intermediate species.

Anesthetics, Local↗
PubMed1985

Calcofluor and ink-potassium hydroxide preparations for identifying fungi.

Calcofluor and ink-potassium hydroxide preparations identified Fusarium solani, Aspergillus fumigatus, and Candida albicans, the three most common ocular fungal pathogens, in scrapings, biopsy specimens, and tissue sections of corneal mycotic infections in rabbits. These stains also identified fungal organisms in specimens from four human patients with keratomycoses. Neither procedure requires more than a few minutes to perform or extensive training or experience to interpret. The specimen stained with calcofluor can be examined immediately, but may not identify all fungi. The more sensitive ink-potassium hydroxide preparation should be examined after 18 to 24 hours, and is less likely to provide false-positive results than the calcofluor method.

Animals↗
PubMed1995

Immunolocalization of fibronectin during the early response of dog dental pulp to demineralized dentine or calcium hydroxide-containing cement.

The role of fibronectin during the events initiating the post-developmental histogenesis of dentine was investigated by exposing the pulp to implants of autogenous demineralized dentine or calcium hydroxide-containing cement for short periods. Implants exposed for 3 days were processed for immunoelectron-microscopic analysis of fibronectin adsorption on to their surfaces. The localization of fibronectin in the critical area of interaction was examined by immunofluorescence 6, 14 and 21 days after implantation. Heavy adsorption of fibronectin on to the dentine implants and the crystalline structures that had been deposited on the cement implants was demonstrated. Positive fluorescence was consistently seen around dentine implants. Strongly immunopositive fibroblast-like cells and weakly reactive, differentiating odontoblast-like cells were found in association with the implanted matrix. Uncalcified matrix secreted by the polarized or non-polarized cells was consistently rich in fibronectin. Fibroblast-like cells exhibiting intense immunoreaction only at 14 and 21 days were mainly associated with the crystalline precipitates on the cement surfaces or within the surrounding pulp. The findings indicate that the specific inductive effects of demineralized dentine on pulp cells are initiated by exposure of the pulp to a fibronectin-containing surface; adhesion of pulp cells and synthesis of a fibronectin-rich matrix characterize the development of new dentine. The reparative response to non-specific inductive influences such as calcium hydroxide seems to be mediated by progressive enhancement of fibronectin synthesis in pulp cells.

Adsorption↗
PubMed1988

A hydroxide ion carrier in planar phospholipid bilayer membranes: (C6F5)2Hg (dipentafluorophenylmercury).

Although a number of molecules are known to function as current-carrying proton carriers across lipid bilayer membranes, no such hydroxide ion carriers have been found to date. We report that (C6F5)2Hg, which can function as a chloride ion carrier, can also carry a hydroxide ion. In 100 mM Na2SO4 solutions, membranes treated with (C6F5)2Hg are almost ideally selective for H+/OH- between pH 6.0 and 9.5. Membrane conductance varies linearly with [OH-] over this pH range and with the square of the (C6F5)2Hg concentration. The presumed current-carrying species is the dimer [(C6F5)2Hg]2OH-, which, along with the neutral molecule (C6F5)2Hg, shuttles back and forth within the bilayer. In 0.2 M NaCl at pH 9.5, the OH- and Cl- conductances are approximately equal. Thus, the carrier displays an approximately 10(4)-fold preference for OH- over Cl-.

Electric Conductivity↗
PubMed1990

Group IIIA-metal hydroxides indirectly neutralize the voltage sensor of the voltage-dependent mitochondrial channel, VDAC, by interacting with a dynamic binding site.

The voltage-dependent, anion-selective mitochondrial channel, VDAC, undergoes two different conformational changes from the open to a closed state under positive and negative applied electric fields. Micromolar quantities of aluminum hydroxide and other metal trihydroxides have recently been shown to be able to inhibit this voltage-dependent closure (Dill et al. (1987) J. Membr. Biol. 99, 187-196; Zhang and Colombini (1989) Biochim. Biophys. Acta 991, 68-78). It was suggested that the inhibition results from the neutralization of the positively charged voltage sensors by the metal species. In the present study, the dynamics of the metal-binding site accompanying channel closure was investigated by adding In(OH)3 to only one side of the membrane and examining its effect on the channel's gating processes. Indium added to open channels inhibited channel closure only when the metal-containing side was on the lower potential side of the applied field. If indium was added only to the higher-potential side, the channels closed and tended to remain closed after the field was abolished. The addition of metal hydroxide after closing the channels with a negative potential on the metal side did not result in channel re-opening as would be expected for sensor neutralization. Inhibition occurred immediately, however, if the channels were first allowed to open briefly. The closed-state selectivity seemed to be very similar in the absence or presence of the metal, indicating that the metal-binding sites are not located within the pore of the channel in the closed conformation. The results are consistent with a voltage-dependent translocation across the membrane of each of two metal-binding sites on VDAC. This translocation is tightly coupled with channel opening and closing.

Anions↗
PubMed1977

The adjuvant activity of saponin and aluminium hydroxide for promoting reagins.

Saponin and aluminium hydroxide were compared as adjuvants for promoting serum reagins in cattle using BHK cell lysate as allergen and the passive cutaneous anaphylaxis test to demonstrate the antibodies. Saponin was the better adjuvant and provoked reagins in all the injected cattle while aluminium hydroxide did so in only 2 or 5 animals. The titres were also higher in the former case. A combination of both adjuvants stimulated reagin titres marginally higher than saponin alone while BHK cell lysate without adjuvant failed to provoke demonstrable reagins.

Adjuvants, Immunologic↗
PubMed1979

Root canal treatment with calcium hydroxide. I. Effect of overfilling and refilling.

Root canals of dog premolar teeth were negotiated and overfilled with calcium hydroxide paste. After 30 days, half of the treated teeth were refilled up to the apical limit. Root canals not filled were considered as the control group. Ninety days after the first treatment, histologic analysis showed more favorable results in the refilled root canals. The overfilling elicits calcium hydroxide resorption and the ingrowth of periapical connective tissue into the root canal.

Animals↗
PubMed1989

Bacterial growth inhibition produced by root canal sealer cements with a calcium hydroxide base.

Inhibition of growth of six bacterial strains produced by two root canal sealers with a calcium hydroxide base, CRCS and Sealapex sealers, is studied. The results are compared with those obtained with two zinc oxide eugenol sealers and one epoxy resin. The inhibition produced with the calcium hydroxide sealers is similar to that obtained with the other sealers. The component of paraformaldehyde in a sealer increases the inhibition significantly.

Bacteria↗
PubMed1990

Apical closure of mature molar roots with the use of calcium hydroxide.

Calcium hydroxide may induce apical root closure in affected mature teeth as well as in immature teeth. Once an apical hard tissue barrier is formed, a permanent root canal filling can be safely condensed. Two cases are described in which calcium hydroxide induced apical root closure in mature molar teeth where the apical constriction was lost because of chronic inflammatory process.

Adult↗
PubMed1991

The comparative antimicrobial effect of calcium hydroxide.

The antimicrobial effectiveness of calcium hydroxide, camphorated paramonochlorophenol, and formocresol in root canals of extracted human teeth was compared. Canals in single-rooted teeth were enlarged and inoculated with Streptococcus mutans, Actinomyces viscosus, and Bacteroides gingivalis or Bacteroides fragilis. After treatment with a test agent and sealing and incubation for 1 hour, the canal contents were analyzed for the number of viable test bacteria and compared with that of inoculated teeth not treated with test agents. All test agents exhibited antimicrobial activity against all bacteria, with percent reductions in viable bacteria ranging from 64.3% to 100%. The combined data for Pulpdent paste and calcium hydroxide showed significantly higher antimicrobial activity than the combined data for camphorated paramonochlorophenol and formocresol for S. mutans and B. gingivalis or B. fragilis but showed no difference for A. viscosus.

Actinomyces↗
PubMed1982

Behavioral and electrical correlates of absence seizures induced by thalamic stimulation in juvenile rhesus monkeys with frontal aluminum hydroxide implants: a pharmacologic evaluation.

A new method for producing electro-clinical correlates of absence seizures (petit mal epilepsy) in conscious juvenile rhesus monkeys is described. A behavioral arrest reaction associated with concomitant 2 1/2 to 3 Hz spike and wave electroencephalograph (EEG) after discharge pattern, was obtained by thalamic stimulation in monkeys with bilaterally symmetric aluminum hydroxide (Al(OH)3) lesions in anterior premotor cortical areas. The characteristic behavioral and EEG features associated with absence seizures appeared reproducibly, 63 +/- 5 days after aluminum hydroxide cortical implantation. This test system distinguishes between anticonvulsants that are effective in generalized seizures of the absence type and anticonvulsant drugs that are effective in focal seizures. Clinically useful anti-absence drugs, such as ethosuximide, sodium valproate, clonazepam, and trimethadione, are effective in this model. Diphenylhydantoin, which is contraindicated in absence states, increases the spike and wave after-discharge pattern. The limitations, advantages, and potential usefulness of this model in predicting anti-absence activity as well as the incidence of side effects of new drugs is discussed.

Aluminum Hydroxide↗
PubMed1995

Adjuvanticity of aluminium hydroxide and calcium phosphate in diphtheria-tetanus vaccines--I.

The potencies of two diphtheria-tetanus vaccines (DT) adsorbed to either aluminium hydroxide or calcium phosphate were compared in mice and guinea pigs. The vaccines were made from the same batches of purified toxoids and contained the same amounts of antigens. Immunizations were done once or twice with different doses of vaccine injected undiluted, diluted in saline or diluted in the corresponding adjuvant. The various potency assays showed that the adjuvanticity of calcium phosphate was lower than or equal to aluminium hydroxide. Despite the range of potency assays done, none of the methods reflected the efficacy of these vaccines in revaccination of humans. A simplified potency assay is suggested for release of final vaccine formulations to reduce the number of animals in quality control.

Adjuvants, Immunologic↗
PubMed1995

Booster vaccination against diphtheria and tetanus in man. Comparison of calcium phosphate and aluminium hydroxide as adjuvants--II.

Diphtheria and tetanus antibody levels were measured before and four weeks after booster vaccination of 313 Danish military recruits participating in a clinical trial to compare aluminium hydroxide and calcium phosphate as adjuvants in diphtheria-tetanus vaccines (DT). Twenty-eight percent of the men had a diphtheria pre-vaccination content below a protective level of 0.01 IU ml-1. The calcium phosphate adsorbed vaccine showed the highest efficacy for both antigens. Adverse reactions were rare but more frequent in the calcium group than in the aluminium group. No correlation was found between pre- or post-vaccination levels and adverse reactions and both vaccines gave rise to specific IgE formation. The results show that calcium phosphate is more effective but not a safer alternative to aluminium hydroxide when compared in vaccines containing 1.0 mg ml-1 of Ca or of Al.

Adjuvants, Immunologic↗
PubMed1991

Calcium hydroxide in restorative dentistry.

This paper reviews the various calcium hydroxide preparations available for use in restorative dentistry and their constituents. The significance of individual constituents in relation to the properties of such materials and their mode of therapeutic action with respect to the dentine pulpal response and antibacterial activity is discussed. Applications of calcium hydroxide in restorative dentistry are also reviewed.

Calcium Hydroxide↗